Yes, changing positions i.e. if he is a striker playing on the right then try him on the left, if he is a central midfielder playing middle then try him middle left or middle right, same thing applys to DCs, another thing to look for is what foot he kicks!, if its left then play him in left positions if possible. Formations play a big role too!, some players play better playing certain formations!, even orders will contribute to it!.
If none of these work then the chances are you have bought a dud!, if he was not hot prospect or scout then yes you have.