My todays post for the How to carry series sucked hard and I will write another later the week (most likley about motivation and stuff). I just made a list of the Lane and the carry-potential:
In the Top Lane you will farm very much. The game is not focussed on killing the enemy but on farming creeps. You should pick a Champion with good sustain and farming abilitys. In SoloQ Top Lane is not focussed on ganking and you will need to win the Lane alone. If you are able to farm good enough you will be able to carry.
Carry potential: 8/10
Here is normally the AP nuker. Mid Lane gets ganked very often normally and is a focus of fights. Try to win the Lane with killing the enemy and killing the tower and ganking BOT and TOP. If you win this Lane, you can carry easily too.
Carry potential: 9/10
Bot Lane is not focussed on ganks, but will get some. Pick Champions that can be defensive farming and aggresive killing. Here you need to get to late Game till you will be able to carry the Game.
Carry potential: 5/10
The Jungler should be able to clear the jungle very fast in order to compensate unsucessfull ganks. Try to find a good ratio between ganks and farming. Try not to get behind and try to counterjungle the enemy, so he gets behind and can't help his team. The jungler depends on the rest of the teamsetup very much, but if the situation fits he can carry very well.
Carry potential: 2-8/10
Yes you saw right, no Lane has 10/10 potential alone, it's always depending on picks, jungler and stuff.