Because Nidalee can transform into a cougar, she has two sets of abilities. One ability set for when she is in human form, and a different ability set when she is in cougar form.
Javelin Toss/Takedown - [Q]
* Javelin Toss: In human form, Nidalee throws a spiked javelin at her target that gains damage as it flies.
* Takedown: As a cougar, she grabs her opponent by the throat and attempts to bring them down, dealing more damage based on how wounded the target is.
Bushwhack/Pounce - [W]
* Bushwhack: In human form, Nidalee lays a damaging trap for unwary opponents that, when sprung, reveals the target and reduces their armor and magic resistance for 12 seconds.
* Pounce: As a cougar, she pounces forward, dealing a small amount of damage when she lands.
Primal Surge/Swipe - [E]
* Primal Surge: In human form, Nidalee channels the spirit of the cougar to imbibe herself and her allies with increased damage and attack speed for a short duration.
* Swipe: As a cougar, she rapidly claws enemies in front of her.
Aspect of the Cougar - [R]
Nidalee changes her form, switching her ability set in the process. Leveling up this skill improves Nidalee's cougar form abilities.
Moving through brush increases Nidalee's movement speed by 25% for 2 seconds.
If there is a jungler on the enemy team, smite or no smite if there anybody you feel might take a rune at level 1 your first ability should be [W] - Bushwhack. Quickly run over to the enemy rune which is generally Golem for most champions and start dropping them into the brush. If you have a jungler of your own, it's good to get this first too so you can protect him safely without being there, at the very least it will give him warning if someone tries to gank or smite steal.
If nobody looks to be jungling at level 1 and everyone goes to their lanes first you can get your Heal first for some good harassing right at level 1.
E, W, E, Q, E, R, E, Q, E, Q, R, Q , Q, W, W, R, W, W
Something like that, hopefully I didn't mess it up but basically you want to max heal first. Take Down base damage is the same 6-10 and 11-15, ranking up Q doesn't make you hit harder in cat form, it just makes Javelin stronger. Sometimes I'll go up to rank 3 heal and then put some points into Javelin for early kills if the other team has a lot of squishy casters like twisted fate, but this is only if I'm not worried about getting dropped instantly and need that max rank heal.
1) Cleanse/Flash - Since the patch, this is what I pick... Exhaust and Rally both got nerfed to the point where I don't care to have them. There IS an abundance of ignites though for early game kills, and considering it has the healing reduction effect. Cleanse is the perfect solution. Flash is also an extremely good spell, I use it for tower diving, Flash/Pounce closes a pretty large gap between you and whoever you're trying to finish off.
2) Ghost/Flash - If you plan on getting Mercury Treads because you don't like Cleanse, then Ghost is probably your other optimal choice for both chasing/escaping. Flash, even more so... without cleanse for AP Sion/TF stuns... you'll need flash for these situations.
I generally get Doran's Ring, because I only solo mid Nidalee otherwise I won't play her, and since I've been either using Armor Penetration quints or Movement Speed quints I really need that extra HP at level 1 for the laning phase.
1) Doran's Ring OR Sapphire Crystal + Potions for the Doran's haters.
2) Sheen + Rank 1 Boots
3) The Brutalizer
4) Phage + Rank 2 Boots, Mercury Treads or Ninja Tabi depending on team.
5) Guinsoo's Rageblade
6) Trinity Force
7) Spirit Visage
Ultimately your final Build should look like something like this. Not necessarily in this order either, could always get Spirit Visage earlier than I mention if you need the extra MR and healing.
1) Boots of your Choice - 1000 gold
2) Trinity Force - 4000 Gold
3) The Brutalizer - 1337 Gold
4) Guinsoo's Rageblade - 2170 Gold
5) Spirit Visage - 1350 Gold
6) Bloodthirster - 3200 Gold
Some of you may noticed that I keep changing the guide, changing the build order etc. It's not necessarily that my old builds on the guide were bad, I'm just trying to keep the build up to date with the patch changes, and what I feel is currently best for the average game. Here's some of the reasoning behind the build changes.
For starters, I took Mejai's out of the build completely. The only reason I had it in the guide at all because it gave a decent boost to Primal Surge and Javelin. Javelin is decent early game, but it's really not worth the mana to skill up for harassing in a lane because auto attacking and healing yourself is just way more efficient. If you're not AP, unless someone is really low you're not going to get many kills with Javelin late game. Spirit Visage gives a noticeable increase in your heal, without relying on a snowball item in case the game goes awkwardly south. It's also dirty cheap and gives magic resistance and durability without the expense of Banshee's Veil. It also gives CDR, which is important.. honestly this item is amazing for the price.
The Brutalizer gives damage, armor pen and cooldown reduction for only 1337. Awesome Item for the price.
Guinsoo's Rageblade... hybrid item, but with sheen and the permanent 8 stacks you get for running around in Cougar form makes this hard to pass up, it's a mid-high tier item for only a little more than a BF Sword. Win-Win.
Bloodthirster... a great item for those games that just don't end, those long 45 minute games where it's back and forth pushing and farming and waiting for baron to respawn.
5V5 TEAM FIGHTS
Try to stay in the back initially, let the tanks blow their major cooldowns. Try and focus the low armor/hp targets like casters, if there's stealthers try and predict where they're going to open up from or just wait til they pop out and try and hit them with a trap so they can't restealth. If no stealthers, try and hit the biggest group of targets possible with the trap... it's generally no more than 2-3 but it lowers their Armor/MR by a percent so its very beneficial for your team.
At Dragon & Baron always try and trap the surrounding areas where you're anticipating an engagement, this will give you a few seconds heads up if you have no wards to counter gank.
Try not to just run in like rambo, guns blazing in Cougar form... if you get CC'd or silenece sometimes you don't even have time to escape if all 5 enemies focus you at the same, do hit and run tactics run in, cougar combo in their face and run out if you expect CC to follow, heal... toss some auto attacks at low armor targets w/ some sheen/trinity procs and then shift back into cougar and cougar combo their face off.
The idea is to "not commit" 100%, don't ever go in with the intention of just staying cougar from 100% to 0%. You need to learn the art of dancing!