Help climbing?

Sooo.. recently I got demoted to bronze 1 from silver 5. TBH, i Kinda suck at this game. The main reason why is that I am never able to find a real main... I get bored of champs reallly quickly, so i never get too good at one. For a low-moderate skilled player, what champs would you recommend (preferably melee, high skillcap, tanky but still easy to carry with, and a good teamfighter)