A few days ago I had a really good player in the enemy team who told my why my attacks were useless against him. That really helped. I'd say you don't have to be on the same team. It is enough if you are fair and be able to type and play.
i like to give out free advice to all the assassins when i see they have 10 or so bot kills, except they call me and idiot and that assassin is made to kill people.....they got 1-20 the next couple of games