Ok, I am not the best, but I'll give you a few guides for each lane:
Top: Preferably a bruiser (Tanky but does damage) and literally just farm... Dont need to do anything else. Only help out team in the late game when in team fights. Good top laners IMO are:
Bruiser riven
Cho-gath
Sion
Zac
JG: Preferably a tank just in case no tank top laner. Needs to be able to kill and assist. Preferably have some form of cc. Good JG IMO are:
Lee sin
Yi (He is 2 ez to play)
Jax
Fiddlesticks
Amumu
ADC: Farm and poke if anyone gets near you. Communicate with your support so you know when they are going in. Must build a lot of damage and stay behind the team in fights. Good ADC IMO are:
Tristana
Caitlyn
Lucian
Support: The linchpin of the team, absolutely crucial all game. I do not suggest going this person if you main zed mid (even if I have but I played supp since lvl 15). MUST have a lot of cc and preferably a tank so they can deal their cc. Aim the people who do damage which are usually the mid and the adc. Some good people to play as supp IMO are:
Leona
Blitzcrank
Thresh
Hope this helps :D