Lulu is a great allround controler-enchanter pick. Although you'll have a hard time carrying with her, if you play her well you can be an invaluable asset to your team by increasing max hp, dishing out shields, speeding people and turning enemies into cupcakes.

Using Polymorph (W)
During the laning phase, your W should be saved for polymorph, not attack speed.
Lulu's W cooldown is pretty long, so taking full advantage of that polymorph is important.
With this in mind, during a fight you should polymorph the ADC (or support if they are more of a threat) as soon as your ADC begins autoing them.
This allows your ADC to get a few extra hits on your opponent.

Lulu's Q does a good amount of damage in the early game, so use that to your advantage. Poke the enemies down with your Q, but don't waste all your mana.

Lulu's mana absolutely sucks during laning phase. In order to conserve your mana and be able to stay in lane longer, you'll have to pick and choose which abilities you want to shield you and your ADC from.

For instance, if it's an auto that does very little damage, don't waste your mana. But if it's a fully charged Varus Q, you'll want to pop that shield.

The game is to pick 2-3 allies you will keep an eye on the entire game and support specifically them to ensure they get fed.

If your ADC is terrible at csing and doesn't understand how to play safe but your mid laner is already 3/0 at 8 minutes, you're better off leaving your lane. Push the wave in with your ADC, go roam mid and hope to get your mid laner a kill. If your ADC pushes up with the wave, help the push and then leave lane.

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