Reach E1 rank in ranked match - 20G
When you begin playing in Xbox LIVE ranked matches you start at rank E5. In E rank if you lose a match you still gain a minimal amount of EXP. To reach E4 you need 600 EXP, when you reach that milestone then you begin with 200 EXP and you need 600 EXP again to reach E3. So the EXP requirement to reach E1 is as follows:
Rank E5 - E4 - 600 EXP
Rank E4 - E3 - 400 EXP
Rank E3 - E2 - 400 EXP
Rank E2 - E1 - 400 EXP
So you need a total of 1,800 EXP total. This is quite easy while boosting with a friend of comparable rank. Edit your license to an obscure title, when searching for opponents you will know it is your friend by the title and location on the map as well. You have 10 seconds to back out before the match begins. If boosting with a friend is should take less than 1 hour to reach Rank E1.