US Dads: any tips to help my son in football?

My son (10) has been playing (American) football for half a year now. As we are from Germany neither me nor any more of my friends have ever played football (I barely know some rules now ;).

My son plays receiver position, but has the feeling he's not good enough, so he wants me to practice with him. Do you have any tips on what I can practice with him besides catching ball?