You can view the requirements for any of the medals, as well as your progression towards obtaining them, by hitting the back button when you are not in an event. I will go ahead and list the silver medal requirements here for convenience, as well as my tips for obtaining them.
Gem Collector – “Finish in Diamond Bracket 5 times in a Global Event (awarded after While You Were Away earnings)”. To easily do this, set up a custom event and complete it. You will automatically finish in Diamond since you are the only one competing. Set the time left to 10 minutes so you get your reward quicker. Once you have successfully finished 5 times in Diamond, exit to the dashboard and load up the game again. You must do this to collect the medal. This applies to any medal which says “awarded after While You Were Away earnings”.
Elitist – “Finish in Platinum Bracket 5 times in a Global Event (awarded after While You Were Away earnings)”. I would recommend entering into an event (preferably a Survive Event) with few riders and little time left (obviously make sure there is enough time left for you to actually complete the event). Get into the Platinum Bracket and then die before you qualify for Diamond. You just have to hope no one knocks you out of Platinum before the event ends, but this should not be much of a problem if the event is close to ending.
Fancy – “Finish in Gold Bracket 5 times in a Global Event (awarded after While You Were Away earnings)”. Follow the same strategy outlined for the Elitist medal, but instead finish in Gold Bracket.
Not Last! – “Finish in Silver Bracket 5 times in a Global Event (awarded after While You Were Away earnings)”. Follow the same strategy outlined for the Elitist medal, but instead finish in Silver Bracket.
Competitive – “Compete in a Race Event 10 times”. You do not need to place in a bracket for this. Also, custom events count towards this provided you set them up as a Race Event.
Check Me Out! – “Compete in a Trick Event 10 times”. Again you do not need to place. Custom events count towards this as long as you set them up as Trick Events.
Risk Taker – “Compete in a Survive Event 10 times”. Do not need to place and custom events count towards this if you set them up a Survive Events.
Customer – “Compete in a Custom Event 10 times”. It does not matter what type of event you set up, they all count towards the medal.
I Want To Belong – “Play in a Global Event with 15,000 or more Riders”. As of March 9 at 12:35 am (GMT – 5:00) the Trick It! Event on The Big Show run (on Boris in Siberia) has about 14,500 riders with 4 days and 2 hours left. There is no drop cost for the event. This should easily hit 15,000 before the event is over (though I doubt it will reach the 50,000 riders required for the gold version of this medal). Once the event hits 15,000 riders, compete. You need to wait until after there are at least 15,000 riders or you will not get the medal. If you happen to have already competed in this event, you should be able to replay it when there is a sufficient number and still get the medal. That is what I did when I got the gold version of this medal. If you miss this event, you might get another chance since there will likely be another free week-long event set up after the current one ends. I don’t know this for a fact so it is better to get this as soon as possible.
Exclusive – “Join an Event with a 100,000 credit Drop Cost”. Make sure you do the bronze version of this medal first (“Join an Event with a 10,000 credit Drop Cost”) and before trying for the gold version (“Join an event with a 1,000,000 credit Drop Cost”). I believe these medals must be earned in order, they do not stack. I cannot personally confirm this, as I went after them in order, but I have heard people saying that is the case. Regardless, better safe than sorry since I doubt you want to waste your credits. There should be several events with at least a 100,000 credit Drop Cost at any given time, so just look around for them.
World Warrior – “In Global Events, earn more than 100,000 SSX Credits lifetime”. This come naturally as you obtain the other silver medals. You can see your total lifetime earnings on the main menu screen (where you can select either World Tour, Explore, Global Events, and RiderNet).
If I can do anything to improve this solution, please leave a comment to explain.