If you have 2 or more players, check and make sure you're not coaching one of them.

The only real way I know of improving relations with players, is by talking good about them in interviews and maybe before/after matches? I think for the most part you have to be coaching them. So on the staff screen, make sure you're coaching the player you want to be improving with.

I know it isn't much help, but it's all I got for you.