First of all, hi and welcome to my first guide!
This build is my mostly-used build as Nidalee.
It's AP-based, so the most skills make ubermuch dmg.
I'd recommand this build only if you know Nidalee etc.

I take as many AP runes as possible, cuz u get the magic pen. with the items.

The masteries are simple:
-Mana regen:So you don't have to recall for mana. That means more mana=more heal=more laning time=more gold/exp!
-Why no cdr? Nidalee's skill have already a low cd, so I don't recommand cdr masteries/items/runes.

1: I start with Boots of speed (followed by Sorcerer's Shoes) and 3 mana pots.
The pots'll hold you longer in lane.
2: I begin with guinsoos rageblade at lv6. With Nidalee's ult, this item is awesome!
3: I'd buy archangel staff, spam your skills as a cougar and see how your mana & your AP raises!
4: Lich bane! A must have item as a AP Nidalee!
5: Rabadon's Deathcap, Don't think that I need to explain that.
6: Void staff, for the 40 magic pen. & 70 AP.

It's very important to max your heal as fast as possible. Ofcourse 'Aspect of cougar' has priority.
Heal keeps you in lane and gives a great attack speed bonus.
My skill priority goes like:
Cougar > Heal > Spear > Bushwack

~†Pros†~
-Spear can be used as a nuke <3
-With much AP your trap does outstanding damage for a trap,
-You can jump trough many walls,
-Passive can be used to chase down your foes or to escape quickly
-Very low cd @ 'Aspect of the Cougar'
-Awesome combos
-Dangerous gankmate.

~†Cons†~
-Takes a while 'till you know how to play her right,
-Kinda squishy if u don't pay attention to your foes.

Teamwork is very important!
You should spam your heal on your mates for the Attack boost.
Finish your foes with your Spear, but don't ks to much (: