Jinx: all u need to do is position properly in teamfights, get your passive off, and you win
Lucian: use your skills in the correct order, and ALWAYS autoattack between abilities, so you get off the double auto
cait: traps traps traps. this is what makes a good cait a great one. place your traps well and at the right time and you are so strong. then just position well and you will win
vayne: auto, q immediately then auto again for a quick burst, and then you can e to pop your w. When you have your ult up, dont feel the need to autoattack right after you q, you have a full second you can stay invisible for. It really comes down to how well you can kite and whether or not you can hit people into walls or not
mf: fk this champion plz dont play her.... if u do all u have to do is kill a minion with ur q so it bounces and crits a champion behind that minion. then just line up good ults and you can do 5k dmg in a teamfight in the matter of 3 seconds.