I'll make this build short like Lulu. lol
I love this new little champ cause she is cartoon-like and CC heavy which give me tons of damage...errmmm damn you phreak i mean tons of fun :D

I also mainly play 3v3 but lulu is not as bad as you would think in 3s. Try her out with a couple dpses. One hard core like trynd or smth like that and a tanky one like nasus or ww..
Kicks *** with this build.

Thats my standard caster runes when I dont have mana problems (Philosophers ftw). Alternative way would be mana reg/lvl seals or pretty much any other caster rune u prefer. I just use those and work pretty well. I like the ap boost from my runes since Im not buying many ap items.

Pretty standard here too. I prefer going 9 on offense than 9 on defense since my build is pretty tanky anyway and I have lots of mobility to get away most of the times.

Like the title says its an aura build so I put all my favorite items in there and you can choose. I usually go for the stone first cause of the extra income. Then I like the cdr from the Gem and I usually support DPSes in 3s so I get starks which is actually pretty decent for you too since your passive appreciates some extra attack speed. After that u can either go for the Reverie if you want the extra cdr fast or I usually prefer going for aegis of the legion first and let the Stone give me some more gold first. AFter Reverie if you got casters in your team a good choice is Will of the ancients and last but not least Rabadons. If you dont have many casters or you got an opposing team with lots of ad you can opt for Locket of the iron solari.

As for boots I prefer swiftness 70% of the times cause I like to be a fast little yordle! :D
Unless we deal with stunners or caster heavy team when i go for the Mercs.

Squirrel Power! As a supporter this W skill is the most powerful CC in the game since it can silence anyone (yes even that annoying Trynd Diver)
You want your Q first for your slow in ganks etc. 80% at lvl 1 is pretty decent.
And you max your E second for the shield and also the nice damage it makes if u combine it with your W (Ap boots).

I wont say much about anything else and let you enjoy the champ on your own.
Just remember what every support should. Buy wards, let your teammates get the kills, zone opponents, and play smart!

Have fun guys!