Pretty easy, but requires a long amount of time spent on the game.
As you play the game you earn SEGA miles. The better and longer you play the more you earn. As you build up SEGA miles you can use them to buy Courses, Music, and Character (a neccessity for the other achievements). Some items cost more than others.
NOTE: Spending SEGA miles does not take away from the amount of SEGA miles you have actually earned. That is to say, if you spend SEGA miles in the shop, it doesn't take away from the Licence colour achievements.