This is my guide for ad/ap Lulu and as I said in the title this is NOT A TROLL so please take this guide seriously. I hope you enjoy it!!
p.s. this is my first guide

For runes I get 9 Greater Glyph of Ability Power and 9 Greater Seal of Ability Powerfor some extra ap, 9 Greater Mark of Attack Speed for some attack speed, and 3 Greater Quintessence of Magic Resist for some magic resist.

For masteries I pick 29 0 1, mostly picking on offense with basic attack and ap masteries and taking 1 on Summoner's Insight which will help your summoner spells Clarity and Flash which I will explain later in this guide why I chose these spells.

For items i get an amplified tome to give some ap and a Health Potion for obviously many reasons I think most of you know.Then you get an Ionian Boots of Lucidity for some cooldown reduction so you can cast Whimsy which is a silence that will help you for 1v1ing other champions. Then I take a Malady. I know I will get many complaints from people asking why a malady? Its very underpowered for what it costs 1825 , but in this situation it is very helpful giving you some attack speed and ap which you want for this build plus it gives you 30 extra magic damage plus Lulu's passive. Then you get a Lich Bane and Wit's End both giving you magic resist and extra damage while Wit's End giving you some attack speed and Lich Bane giving you some ap. Then you finish it off with a Guiunsoo's Rageblade and Phantom Dancer both giving you attack speed while Guiunsoo's Rageblade giving you some ad and ap and Phantom Dancer giving you some crit. chance. I think most of you notice that some of these items give you some extra movement speed like Lich Bane and Phantom Dancer and using this increased movement speed with Whimsy increase Lulu's chance of escape and retreat and gives more utility to her.

For summoner spells you want to get Flash and Clarity using flash as an escape tool while also using it to hunt down enemies and using Clarity so you wouldn't have to recall when you're out of mana or so you can get away by using one Lulu's abilities to slow an opponent chasing you if you are out of mana.

For skill sequence I take each of the skills early so you can fully utilize each of her skills while afterwards you want to only focus on Glitterlance and Help! Pixie and taking a skill point on Whimsy afterwards because whimsy at level one is already helpful.
And as usual take your ult at 6, 11, and 16

For farming you always wan to take last hits on minions and once you get malady this will get easier. If you go bot or top with a range with ad/ap Lulu its easier for you to farm early game (trust me it is). Also a technioque to farm with Lulu is to aim for minions in the back so her pixie's bolts will hit the ones in the front while your basic attack will hit the one in the back enabling you to gain more exp hopefully killing the one in behind and geta share of some exp from the one in front because all champions within 1600 range gain a share of the exp of a killing of a minion.

You want use her by first use Whimsy to silence them then use help pix! applying some damage, letting you see them. and not let the bolts block,[*] then use Glitterlance after whimsy is gone even more slowing them. And while all this is happening attack them applying tons of damage while the champion is near your range and with Lulu's slow it helps do that.

As for all mages if you are going against a melee type you want to try to stay away as much as possible, don't just go charging in right next to the opponent champion, you will get easily killed