You have Flash for obvious reasons, but the ignite can be disputed sometimes. Some people recommend taking Teleport or Barrier, but I do not think that is the right way to go. If you want to help a lane other than your own, you generally will just wander there instead of using a teleport, and if you are good at dodging skillshots, there is no reason to take Barrier except on a few rarer occasions. Ex. Veigar ultimate, Syndra Ultimate.

For the offensive start, you will want to play aggressive, and try to deal a ton of damage when you hit level 2, cast your W close to them, so they are not as likely to be able to dodge your Q's.

Your Q is your more safe poke, but can be used when you are going for an engage. Also, you will get more value when it is combined with your W. That is why you max Q first. On your first few times, you will not use your W as effectively/ efficiently as you will be able to after some practice with it. That is why you do not max your W second. Your E is a high-damage high-risk ability that you generally only want to use if your shadow would be the one damaging the enemy, or you and the shadow are doing the damage. So, if you are trying to go for the all-in, the combo I recommend is W-Q-W-E- then ult if you have it.

So, now that you know the basics to Zed, have fun dominating with him on the Fields of Justice! Good luck!