Not Updated For Current Season
Note: This is not a Level 30 build. This is the current build I use to play 3v3 at my current summoner level (as it stands, 12) and trying out in 5v5. I'm posting this purely because, as a new player, I have found it quite hard to find things tailored to the lack of runes and mastery points one has at higher levels. I'm also using this as a way to learn how to properly build my Champion, so please, constructive critism is a must here. :D
I'm not gonna go into too much detail about my rune/mastery selection as I'm basically going for things that I can use accross multiple Champions.
My rune selection was based off multiple caster champions that I've been playing. I've found that it's not making a huge difference at this level (of course, I don't expect that to stay the same). Magic Pen on my marks, AP/18 for my glyphs and seals, and my quintessence is cooldown merely because I've been lazy and haven't replaced it with anything else yet.
Being level 12, I don't have much to work with. However, I have found that sticking with the utility tree keeps me going. I'm still trying to master last hitting, so Greed is in the mix to help out with item costs. All my points are placed with the assumption that I will not always being playing Zilean.
Alright I know that I will get hit for using Clarity if I don't explain myself... So the purpose of this is actually broken into 2 reasons. In the early game, I have a tendancy to either be teamed up with or single handedly start bombing the **** out of enemy champions. Therefore, I run out of mana quick. This allows me to stay in long enough to grab my first set of items and be efficient enough to press into mid-game fairly well. The other reason is for a similar case. Late-game, I find myself doing a ton of bombing runs (as well as keeping our main attention lover aline). These tend to take a toll on my mana if I don't end up dead. I know, I know. It's not the BEST option for me to take, but so far it has fit my playstyle. Who knows, later on in summoner levels I may opt for mana regen instead of all that extra AP.
I've considered taking Flash or Teleport (a friend plays a very interesting Jax and loves to Teleport everywhere, so keeping up with him is sometimes a pain). Whether I do this soon or not I haven't decided.
The whole idea to this build was to amass the AP I would need to take out high health champions or rain down some heavy AoE. This is how I've been building my items almost every time. The only difference I've been making has been dependant on how aggressive the group has been. For aggressive pushes, I'll grab Lich Bane before Frozen Heart and sometimes even before Zhonya's Ring. If we're stuck in a bind, however, it's what you see above that usually gets done.
The Amplifying Tome is a standard for me, bar none. Potions I typically ignore since it's rare I actually let myself get into a ganking position (and I'm normally dead before it's of use anyway). From here I stay in lane and focus on my last hitting as best as I can while harassing the enemy champions. My first trip back will either be by death or when I can make my Kage's (again, I'm still mastering last hitting) and get my Boots of Speed... unless I forget to head back, in which case I grab whatever I can to start building my Codex. From here it's back and forth through the game grabbing my Sorcerer's Shoes first, work on Stinger to get Nashor's. Glacial Shroud is usually needed by this point, so I grab that next. Void Staff is thrown in mostly because I'm a slave for the magic pen. After this, however, it's entirely based off what I'm doing with my lane-mate and what I'm facing up against. Lich Bane has more often than not taken the spotlight quickly. Whatever I end up taking for my sixth item, however, is where I say bye bye to Kage's Lucky Pick.
There you have it. This is what I've been doing and it's worked out well thus far. I don't typically pay too much attention to KDR since I'm usually around a lane/team-mate and supporting them, but it's yielded slightly above 1:1 ratio since I've started sticking to this build. I'm still looking for improvements to the item build and trying other various things out so I will hopefully be adding more. I will also be trying to keep this up to do with my current level as well.
Thanks for taking the time guys. Please leave me a comment and let me know what you think. As I said, I'm new so any constructive feedback is appreciated.