My name is Nicholas and I have been playing League for a few years now, I started maining Zed earlier this season, but I have a lot of experiences with him from the past so I mastered(at least decent) him in a few weeks. I really like Zed because of his skill ceiling, you will never get bored of him because you can style on your opponents, and you have a lot of ways to assassinate and escape using W and R. This guide is for the new season and I think this build suits Zed the best, I have a PBE account and I tried this build and I won 10 out of 10 games, hopefully this will work out for you as well, although I do not guarantee it because we all have different playing styles, and I like to play greedy and try doing things like 1v3 and ulting an ADC with an ardent censor support right beside them. Anyways, enjoy the guide.

[AA = Auto Attack]
[You can always add flash and ignite in these combos]

Basic Poke Combo(Explanation: normally use to chunk, harass and make the enemy miss cs)
W -> E -> Q

One Shot Combo(Explanation: use this when you are 100% you can kill the enemy and you have vision around you, your shadow is your only way of disengaging aside from flash)
W -> E -> Q -> W -> AA

Ultimate Combo 1(Explanation: Start off with the basic poke combo to determine if you will get the target low enough to ult, in this case if you do, follow up with an AA(duskblade proc) after ulting and E then ult away)
W -> E -> Q -> W -> R -> AA -> E -> R

Ultimate Combo 2(Explanation: This is more of a kite combo for Zed, against multiple enemies or fighting under tower, W to where you want to go after ulting, then ult, if you have enough health to survive a tower shot and your enemy's abilities, go for q-e-aa, but if you don't, w instantly after your r and do the combo, becareful enemies may try to run to your shadow while you ult.)
W -> R -> Q -> E -> AA -> W

Ultimate Combo 3(Explanation: I use this combo when I know my enemy has a dash or flash, so i start off with ult, wait for my enemy to try to escape and instantly do the one shot combo, but if they don't try to escape for a while then try doing the one shot combo instantly)
R -> W -> E -> Q -> W -> AA -> R
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
There are a lot more combos and these are just the basics. You will be able to create your own combos if you master these combos.