Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
See, the point of this build is to get as many Doran's Rings as you can, and then get enough gold to sell them and buy really big stuff, like Guardian Angel, or Mejai's. It sounds really dumb I know but it works surprisingly well.
Playing this Zilean is pretty typical, Time Bomb harass, speed up allies, revive allies, and Time Bomb "ks".
This is gonna be your favorite spell. Very heavy damage and a variety of uses. If a target with a bomb on it dies the bomb will detonate. You can place bombs on caster minions to keep melee champs at a distance and punk them out of last hits. Eventually they get tired of this and move in. Pay attention to minion health bars. Why? you can place a bomb on a minion near an enemy champ to surprisingly nuke them. You can also place bombs on friendly champions.
Introduced at lvl4, this is a very useful spell. Takes 10 seconds off your Q W E R spells. Its also the bread and butter to your dmg combo. Which is Q W Q.
One of my favorite spells of Zilean's. Give huge movement speed bonus to allies and huge movement speed debuff for enemies. You have to keep in mind that you are very squishy. Common tricks include hasting the fed teammate into teamfights, slowing a runaway champ, hasting a pursuing teammate into enemy champ, hasting a champ that is in a bad position, and running in and out of toward range to insure a clean bomb placement
hasting in a champion that deals damage to an enemy that later dies counts as an assist.
The reason why teammates love you and enemies hate you. Self explanitory. This spell will take the most practice. Sometimes you want enemies to see it and sometimes you don't. Also keep in mind that in crucial team fights you need to keep your carry alive (strongest link).
Zilean is a fairly simple character to use. Hopefully someone else will find this guide useful. Thanks for reading, and remember Q W Q = Win