Why should you play lulu?
Description:
Lulu has solid poke and protecting abilities at the early phase of the game, making her a very universal champion, who can bully enemies, or stay very defensive, causing her adc can be safe.
Runes
Summoner spells
Items
Early Game.
At level 1 Lulu is very strong. She allows you to outpoke enemies, especially if you can bully-engage champions like Blitzcrank, or Thresh because even if they land a hook, they can't do many more. If they waste their hook, you should rush with them with AA, and space them from minions or your adc. If you do it correctly, in the early game you will have more damage than your adc.
Disclaimer, Nautilius is an exception because of his passive, who can cc you twice on 1 level. But if he wastes his Q you can still poke him. Just be careful, it's a skill match-up.
You need to look at the experience bar, because on level 2 Lulu loses her power when enemies expand their skillset. Still your job is to secure your ADC and poke the enemy.
Midgame
At the Mid-state of the game, you can start roaming on objectives, or other lanes, but only if the bot lane is secured. Don't let your adc die because you are not with him. Remember to place wards when you roam, to make vision. Vision is life, especially at squishy targets like Lulu.
Late game
Late game is the time of team fights, so you have to stick to your teammates, but keep your distance from the enemy. If you will go too far, or you will be alone, you will get one shotted.