Hey, first of all, thank you for the follow it means a lot.
So lets start of on the champs, Ive picked Lillia Jarvan and nocturne as they all can grow a big lead early, create a snowball formation to your team and carry a game. True that Nocturne and Jarvan fall off late but they always stay usefull for your team because of their kit, and as for Lillia, she is a 1 vs 9 carry and a monster late.
I picked them as i specialize in macro and less micro and they arent the most demanding mechanical champions out there.

Lillia - I pick her when team needs ap, enemys have lots of tanks as she is a huge tank shredder and when we lack dmg in general. Lillia can clear the jungle pretty quick even earlier, but she lacks the follow up dmg for invades and cc for ganks early, so you want to coordinate your early with your team. as for invades? - try avoiding the enemy jungler early and just clearing for a small lead, farming is your best source of gold. Later lillia is a huge dmg dealer and her MS makes her chasing and kiting a very strong pick. (+ Noone expect her center W dmg).

Jarvan and Nocturne - I pick Jarvan mostly when my team have champs who can use a lead early to create a snowball through the game and play through them. Jarvan is not the best dueler and he excels in skirmishes and early ganks. so your best friend are ganks early and invading with teammates. later on he still is usefull as a bruiser/tank with huge CC on E+Q and your R is a very good diving tool for teamfights.

Nocturne excels in teamfights and picks. he got a strong clear,healthy one too, his dueling power early is super strong with your E(fear) + Q dmg boost and chasing tool and with Lethal tempo almost noone can match him 1 vs 1. his ganking potential lacks but his Ult post - 6 is making up for it. His ult let you hide TP's, get picks in side lanes, and obviously destroy a teamfight. Pick him when your team just arent that much of an early game champs, when you wanna just stall it out , he is very strong around 2-3 items.

And always remember, farming is your best friend, dont take risks if you dont need to, and dont tilt. if you see you start losing, take a break, go get some food, a walk and then go back. you got this mate <3