Most of Riot's tips for playing as/against champions are outdated. So let's make our own!
Remember that the tips don't have to be high-level. Champion tips, generally, are meant to ease people into a champion or to give people little-known tricks of a champion.
Playing as Zed:
Zed's shurikens make up the majority of his burst. Be sure to slow the enemy with your shadows so that you can land your shurikens. Try to anticipate their movement abilities, or wait until they use one before using your shurikens.
You don't have to use Zed's ultimate just as an initiation tool! It makes you untargetable for a short time, allowing you to dodge enemy spells. You can use it offensively and defensively at the same time.
Playing against Zed:
When Zed ults you, he will always travel in a straight line to appear directly behind you, regardless of which direction you yourself are facing. Use this knowledge to prepare any available offensive or defensive spells in his landing area after he's targetable again.
Wait until Zed comes out of his ultimate before you use movement spells, so he won't be able to follow you. As long as he is untargetable, he is able to track your movement.
Playing with Zed:
Zed loves steroids of any kind. Buffing his AD or attack speed while he is beating away at a target under the effects of his ultimate will go a long way in assisting him in securing the kill for your team.
Stunning or snaring Zed's target makes it very easy for him to line up multiple shurikens, which make up the majority of his damage.
Your turn! You can do any champ you want!