All of these characters are solo top and/or Junglers.
Yi on top is trash, so don't play it. Play him as a jungle, he is better that way.
1) In lane, waiit for your minions to get the enemy minions low then last hit it for the gold. Don't push your lane.
2) Buy wards, and ward the river where baron is at. one ward is enough. If you do that, you can't get ganked.
3) You just have to have knowledge off the game.
4) Some runes help ALOT. For example check my rune pages for Olaf. If you go with these runes, the enemy lane will have it really hard to beat you later on when you get a Wriggles.
5) As Yi, come in later after the team has burned all of their spells. Then ult, alpha strike to the enemy AP carry or AD carry and kill them
6) Call MIA's, usually people get mad when they get ganked from other lanes when you didn't call MIA. This however, is their fault because they overextend, and have no map awareness. However, call it anyways because they will get mad at you
7) Have map awareness. If for example you are top, and there is a small fight happening near the river where Baron is at, go down their and help out your team.
But I would say, try to learn how to jungle as Yi. He isn't a good top character.