Well, I don't know how you play but I play 4 defenders, 2 dm, 2 wingers, 2 strikers
I bought for my team Darijo Srna RB, José Angel LB, de Rossi DM, Farfán WR and Neymar ST. 1st on EPL, just lost one game to Chelsea.
This suited my tactics. You should buy players that suit yours. The only one disappointing a little is Farfán, but he had one long term injury so it's forgivable.