I always think that the best achievement solutions are the one's that give you significant info on either the a.) easiest way to get an achievement; or b.) the quickest way to get an achievement.
No offense to Bazinga I, but he doesn't really detail either in his solution, so I thought about it for a bit - and came up with a plan that I thought would classify as the "quickest" way to complete this achievement. Unfortunately I fell afoul of some idiocy from EA - so I'm going to both detail what I consider the "quickest" method for completing this achievement AND I'm going to (hopefully) keep you from running afoul of the EA idiocy.
First, this is kind of long, so if you don't want to spend the time to read it all, you can just scroll down to the bottom, I summarize there what I think you need to do.
Also, to be clear (hat tip to Carbokris for suggesting this), your goal is to reach the daily limit of XP in the EA Sports Football Club. That daily limit is 2000 XP. So that's your goal: get 2000 XP in a 24 hour period. You can read below how EA defines a 24 hour period (or a day).
(** Edited Comment (02/10/2013) ** - My proposed "optimal" solution will not work AT ALL (due to stupidity from EA in incorporating a MASSIVE BUG) if you are currently experiencing the most awesomely stupid bug ever from EA Sports. There is a bug in FIFA 13 where you receive ZERO XP for completing an EASFC Challenge. The last five challenges I have tried have netted me 0 XP. This bug is rampant - and EA is aware of it - but until they patch it, if you are under it's throe, you aren't going to be able to utilize the strategy I have outlined below.)
So here is some initial info that I had to learn (because it wasn't detailed anywhere):
First, how do you tell how much experience you have attained for a day? Well, the only place I can find that listed is on the "EA Sports Football Club" screen (in game). You can get to it two ways:
1. You can scroll throught the menus on the bottom of the screen from what I consider to be the "Main Menu" until you have highlighted the one labeled "EAS FC". Hit the 'A' button here and it'll take you to the "EA Sports Football Club" screen;
2. Alternatively, if you are on the "Main Menu" (the initial screen), hit the 'X' button and it will take you there directly.
When you are on the "EA Sports Football Club" screen you will see a list of menus to the left (with "Catalogue" highlighted). At the top right will be your Gamertag. Just under this it will list your level, your "Daily XP", your FCC (Football Club Currency - for buying crap from the Catalogue - does anyone know of anything else you can do with it?), and finally, your "Daily FCC". Of course, we are only concerned with "Daily XP" for this achievement.
The max daily XP you can get is 2000. So that's our goal. Reaching 2000 XP in one day.
But - and this is EXTREMELY important - (mainly because it can come back and bite you in the ass) - you need to know what defines a "day" in EA Sports FIFA 13 land! Well a day in FIFA 13 starts at 12:00 AM (Midnight) London time - and it ends 24 hours later at 12:00 AM (Midnight) London time. (Ok, technically it's called Greenwich Mean Time (GMT), and technically, it goes from 12:00 AM to 11:59 PM - but you get the drift.)
EA - in it's idiotic & infinite wisdom - doesn't make this clear or advertise this fact in any way, shape or form.
So you need to convert that time to your local time - so that you are aware of when EXACTLY the "Daily XP" is going to reset to zero. For me, that means at 5:00 PM MST my XP resets to zero. I have from 5:00 PM MST on one day until 5:00 PM MST the next day to get 2000 XP. I'll explain in a bit why this can bite you in the ass - and give you and example of how it did exactly that to me.
So before I get to what I consider the optimal solution for this achievement, let me give you one additional piece of info: you can find out how much XP you are given for completing a particular task from the same "EA Sport Football Club" screen we use to find out our current "Daily XP". Scroll down on the left hand menu to the "News" menu.
This menu will give you details about your accomplishments, but more importantly will tell you how much XP you have gained for various things.
For instance, "Starting FIFA 13 for the first time" will net you 25 XP. "Playing FIFA 13" (basically, starting it for the first time each day) will net you 10 XP. Obviously, you're not going to get to the limit very easily just starting up the game. In fact, most things you do don't net you very much XP. Completing a "Bronze" skill nets you 20 XP. Downloading the most recent Match Day update nets you a glorious 5 XP.
So what are some things that net you decent XP? Well, match playing mostly. 158 XP for most matches (now, I'm playing on Amateur at this point, so it's possible playing at a higher level will net you more XP - also I'm assuming that winning nets you 158 XP and that drawing or losing would net you less, but I haven't lost or drawn yet, so I have no idea).
Leveling up nets you 350 XP (which will play into our optimal strategy for completing this achievement). And, finally (and most importantly), completing an EA Sports Football Club Challenge will net you 600 XP at Amateur level (win at a higher level of play and you get more XP).
So what is the optimal (in this case, quickest) method for completing this achievement? Well, I believe it plays out like this:
1. You want to do this when you are at a low level. Optimally, you achieve this before you've ever leveled up at all. But getting it when you are under Level 5 would still be feasible. If you are above Level 10 and you haven't gotten this yet, then it's going to require that you play more than one additional match to reach the "max" XP for the day.
2. You want to complete two "EA Sports Football Club Challenges" in one "day" (but again, be VERY aware that a day isn't 24 hours from when you start getting XP for the day (which would have made sense - but expecting EA to make sense is futile) - a day is from 12:00 am London time to 12:00 am London time 24 hours later. You'll have to convert London time to your own time zone. But be aware of that time constraint - otherwise, it will bite you in the ass, just like it did to me.
Completing two EASFC in one "day" will net you 1200 XP - well over halfway to your daily limit. However, EASFC Challenges last exactly 48 hours. Luckily, they start and end a few hours before the end of the "day". This way we're able to leverage the 'difference' to our advantage.
So, for my timezone, a challenge ends about 2:00 PM in the afternoon. At that point a new challenge begins. I can thus, finish the first challenge before the deadline, and then play the new (second) challenge before the deadline for the "day" is hit (which is 3 hours later). So you want to complete the first challenge at the back end of the 48 hours, but leaving yourself enough time to both complete the second challenge and complete any extra matches you need to get to the "Daily Max" while also not running into the end of the "day".
Optimally, you would complete the first challenge slightly before the deadline, then complete the second immediately after the deadline. Again this will net you 1200 XP.
3. Finally, we leverage the fact that leveling up always nets you 350 XP (or it has so far up to my level of 7). If you haven't leveled up very much (or at all, which is best), finishing these two challenges will probably level you up at least once, if not more. At level one, you need 500 XP to level up to 2. At level two, you need another 600 XP to level up to 3. So, if you haven't leveled up at all, you need a total of 1100 XP to level up twice. Level up twice and you get 350 XP per each level up - for a total of 700 XP. Finishing the two Challenges should net you 1200 XP, and thus - if you are starting at Level 1 with 0 XP - you will level up twice due to the XP received from completing the Challenges. This is 700 XP total.
Add the 700 XP from leveling up to the 1200 XP for completing the two EASFC Challenges and you have a total of 1900 XP - just 100 XP short of the 2000 daily limit. At that point you play one EAS FC Match Day game - or one FUT game (or anything that nets you at least 100 XP) and you have "Maxed Out" for the day.
Obviously, if you are at a higher level, you may have only leveled up once - or not at all - in which case you will need to play a few more "extra" matches. But even in that case, playing the two EASFC Challenges in the same "day" will get you to the max XP much quicker than just straight playing matches. If you were to just play matches alone, in an attempt to get to the max, you would (assuming 150 points per match) have to play 14 matches to get to the 2000 XP you need. Even playing 4 minutes halves & on amateur you are looking at anywhere from 3 1/2 to 5 hours of play time. Assuming you play both Challenges & don't level up at all you only have to play 8 matches, which is 2 to 2 1/2 hours. Optimally, you get both Challenges, level up twice & play one more match, which means you only have to play for 1 hour to complete this achievement.
Anyhow, that was the plan. And it should still work for you. Unfortunately for me, I was ignorant of what a "day" meant, and it came back to bite me in the ass.
So the mistake I made was not knowing (thanks to EA Sports being complete douches and not informing anyone of this fact) that the cutoff time was 12:00 AM London time - which converted to 5:00 PM MST where I was at. So I got up at 5:00 AM MST and finished the challenge that was going to end 9 hours later - and got my 600 XP. I then attempted to play a game or two - but as usual the EA servers went down (this actually ended up assisting in screwing me), so I couldn't get any matches in before work.
So I finish work, & I get home at 4:00 PM MST, and complete the new Challenge (which also levels me up from 5 to 6 - unfortunately, I hadn't started at a lower level). At this point (thanks to a few random points from this or that task) I'm just 130 points shy of "Maxing Out". So I go take care of a couple of things, come back in a bit, and start a new match. I finish it at 5:06 PM MST. No achievement. And that's when I figure out that the Daily XP resets at 12:00 am London time - or 5:00 PM MST - 6 minutes too late for me to get this achievement.
So please be aware of the cutoff time - or you too will be cursing the evil that is Electronic Arts!!
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Finally here's the summary (for everyone who didn't want to read the long version):
1. You can find you "Daily XP" total on the "EA Sports Football Club" menu. You can get to that menu by pressing 'X' from the home screen, or selecting it from the menus at the bottom of the screen.
2. The quickest method to complete this achievement is to complete two EASFC Challenges (found on the EA Sports FC menu) in one day (600 points each), level up twice from completing those matches (350 points each), and then completing one more match (of your choosing - I suggest either a FUT match or a EAS FC Match Day Kickoff match) worth at least 100 points. You can find more details about this strategy above.
3. The biggest thing to be aware of is that for FIFA 13, a "day" is defined as 12:00 AM London time to 11:59 PM London time (technically, this is called Greenwich Mean Time (GMT) but whatever). You have to convert that to your local time zone, or you'll bump up against the deadline, your XP will reset, and you'll have wasted your effort.