Well, what have you been playing formation wise? I would start again with a nice basic module (like 4 4 2 or Narrow diamond) whichever your team is best set up for, set it to defensive/mixed and watch some of your matches to see which players aren't ever getting mentioned. You could also play with how you are assigning their points, that can have affect on how they perform. Playing as many friendlies as you can too can help see what players can do well, and which just aren't working for you.