Getting Gold on all of the Events is relatively easy, especially if you are trying for the platinum times. The main things to remember when getting gold is to use the tricks of the game. Each type of event poses a different challenge, but with all the events it is best to wait until you have everything upgraded to truly try to beat the gold time. I also recommend doing these on easy or normal, as it takes less hits to destroy tanks (that way you normally don't have to charge an attack to destroy a tank with the blade power).
For the Combat Events, if their are tanks or helicopters, focus solely on those when fighting to maximize your kill score each of those nets you 10 kills instead of the 1 kill you get per person. Also if you are using the blade just tap Y on the tanks - on easy and normal you don't have to charge to destroy a tank - usually, sometimes you'll have to hit them again. This keeps you moving quickly across the screen. Also if you stealth consume a tank and park it in the area where you need to fight stuff, each tank you have there won't move to attack you, but will count towards your kills once you start fighting and destroy the "empty" tank.
For the glide Events, just getting into the smallest ring will net you the gold, it doesn't have to be pretty or skillful, just glide till your close and drop just a bit ahead of the small circle. Also remember that if you are just slightly off you can quick dash at the last second to get into it. Just a little bit of practice and you should be able to get gold on these no problem.
For the Running events, these are the hardest to get gold on. Just practice your quick-dash-run (just before landing, quick dash and continue to hold the running trigger and you'll be running faster than you would if you just landed) for a bunch of these to get the faster time. Some of these events require you use your quick dash and stay off gliding. gliding will generally slow you down. Also if you have trouble with the ones where you have to get up a building really quick, there is a flying "glitch" that I have found that sends you up a wall fast. If you rapidly tap A and your dash trigger your will basically jet up the side of the building. It takes a bit of practice, and when you get to the top you may end up wasting your quick dash so you'll have to land, but with a little practice, this move got me up the skyscrapers faster than just jumping.
The war events are all time based, so the best bet to do is to use the blade power for most of these where tanks are involved. and use the same combat trick from above. if you have to use a military weapon to beat it, it is best to use a button mashing tactic to just launch as much ammo into everything as possible... make sure that you are always targeting something on the ground though, so if they start to fly up into the air, switch to an enemy on the ground (you don't get any splash damage for hitting an enemy in the air, and sometimes your grenade completely misses wasting time).
Using a bunch of these tactics will help you get this gold achievement, and many of them will even get you the platinum. just remember to always focus on the tanks whenever possible, and to remain calm and focused. a broken controller will get you none of these achievements :)
Oh, and if you are really stuck on anything, just use google video or youtube and look up the exact event you are stuck on, and there are some great hints on what to do to get the gold (and the platinum as well).
This was the toughest one for me to get so I'll get you started with this link... Best bet is if you try for these platinum's, you'll get the gold no problem. Just practice, practice, practice.