I don't care what position you play, If you want to win, Carry.
Now, there are a couple of ways this can be done, but here are the priorities as I see em:
1, Dont Feed.
2, Don't Feed.
3, Don't Feed,
4, Don't be toxic, and by toxic, I mean when someone makes a mistake ... SHUT THE FUCK UP. don't even mention the mistake. Don't say ohh, you should have seen that, or say where the fuck is my wards, or anything. If it's not helpful, like literally saying things such as "Hey, Jungler, stay with X because he needs the backup" or "Damn, I should have warded that bush, sorry" Or anything along the lines of taking the blame or trying to help.... STFU.
5, pay attention to the mini-map for ganks and enemy team. If you don't see the jungler, think of the worst possible position he could be for you, and expect him there. This rule also applies to rules 1-3, but toxicity is so bad for the team I really see it as being more important.
6, If you're a jungler, fucking ping. If not, don't engage without one. I've seen junglers come bot, I've been pushed against the tower, 2 champs almost dead, like 2% health, and the jungler, runs from River to golems or gromp. If you don't ping and you gank, well, too bad for you, thanks for feeding my lane. better you die than the ADC for engaging and you decide not to or we have no fucking clue you're going to engage until you're already up shits creek.
7, If you're playing a Non-kill necessary role(Jungler and Support), remember you're role is to keep the Damage dealers alive, tanks are secondary concern.
8, if you're a tank, pay attention to the makeup of your team. I've seen malphites in games that go Warmogs, Randuins, and Frozen heart against a full AP team.... guess what happened.... Malphite became magmite because his dumbass was melted so quickly.
Anyway, I know that went off topic a bit, but something about this post just hit a nerve!