laning phase as a top lane Zed

Going top with Zed is a fun way to get better at LoL because of how Zed works. Throwing your Q out early game to grab last hits will help a lot when your fighting an aggressive high damage dealer. Using your W>Q combo will help harass with taking minimal damage. Using your W>E combo will help you catch people with your Q to do more damage. If you were to use all of Zed's combos with ease, you could take out an enemy fast.

laning phase as a mid lane Zed

Mid lane Zed is much harder than top lane Zed, and requires more concentration. As a mid lane Zed maxing your E first could be a good option if you wanting to take minions and do less harass. As going mid Zed, you have to watch out for the enemy's high damage harassment and their jungler's ganks. I do not have much experience as mid Zed because I think that top Zed is a better option.

Zed's ult top lane and mid

Zed's ult gives him a great advantage in team fights, allowing you to focus any high damage dealer, or get away from the fight. Zed's ult allows you to jump to target champion and have a BoT(Burst over Time). The damage of the BoT is determined on how much damage you do over the time period it is on him/her. The damage can take out a champion at last second allowing you to get the kill after death. This ult can also allow you to jump on a ADC use your burst run away and have the BoT finish her off, giving you the time to make an escape.