Hi there, this my custom Blue Lulu build which I like to call Blulu. It's very effective in the whole game, because she is hard to be killed, and slows everyone she wants, and she can.

You must never rush an item, always build in parts. Example:
you have 2500 Gold, then buy Sightstone, Fiendish code from the Frost Qeeen's claim, Boots of speed, and Frost fang. You have a lot of items now, and not just one big thing. You have speed, wards, health, and cooldown reduction.

Try to poke enemy ADC-s with your Q, but always be careful to not take damage. You can poke enemies, and even gaining gold by your mastery, and your support item. Don't always use skills, because if your adc engages, you won't have mana to save him, to polympoirph, or slow enemies. Whenever you can, use exhaust on the adc if it is fighting with your allies, and also use it on the adc in teamfights. You should use your W when u are going ahead to ward the dragon's place, bushes, etc so you can ward it fast, without losing a lot of XP. In teamfights Use the W spell on the enemy Mage/Assassin, or the adc. You should use your Ultimate on the allied AoE ability champion, for example when Jarvan is charging, when Wukong is going invisible and ulting, or when a Katarina is engaging with her ultimate.

pros:
Useful in whole game
Easy to escape yourself and your allies from trouble
Tanky and deals damage
Carry style support

Cons:
High cost build
Hard to perfectly learn technic

Don't attack minions with basic, unless your adc agrees to push botlane. Be careful, because your passive can take the creeps, and it disables your support item for a few seconds. When adc is not on lane, try to let enemy minions come near tower, and lasthit with your Q, and basic attack