Ok, the easiest way of getting this achievement, along with the other level based achievements is to play the mini games.
To be able to get this as quick as possible you need to make sure you don't play any mini games, hence set any PBs.
Then you can play each mini game and set the lowest score possible, this will result in a pb and a very decent xp boost. Eg - play the table tennis rally mini game and score 1 then miss on purpose, then play again and score 2 and then miss, then 3, then 4..... Each time you will set a PB and get an xp boost.
Use this same method on all the other mini games and you will level up in no time.
Just remember not to go setting awesome PBs as you will find them hard to beat and not get as many xp boosts!