Need Help Getting Out Of Diamond 5

Looking for some insight on common mistakes with Diamond 5 players from higher elo players. I play mainly jungle and mid, and have been spamming Diana lately since Nidalee sucks now. I don't need advice with champion picks or build paths, just insight on how to play lane and how to transfer a lead in the jungle to my teammates. I also want to know tips on dealing with toxic players, because I have met the worst of the worst of toxic players in the elo, having played in every elo from Silver 5 to Diamond 5.