Nidalee is a great scout. Putting Bushwhack in as many places as possible can warn your team and you about gank attempts or lonely targets in the jungle. Combined with Clairvoyance, Nidalee can grant great map control. Bushwhack is ignored by enemy turrets, but cannot be teleported to.

Aspect of the Cougar abilities cost no mana, so it is effective to use to push or jungle. Pounce can also be used to jump over the jungle walls and escape. Since Pounce costs no mana, it can be endlessly cast which makes it a good chasing and escaping ability.

With good harassing abilities, good farming abilities, good escape abilities, and the staying power of self-heals with Primal Surge, Nidalee is an excellent solo laner and is a good choice to hold the 1v2 top lane if your team has a jungler. (although she does depend on her ult to maximize her farming and escaping capacities, and has more problems with such factors before level 6)

Javelin Toss is useful for champion harassing, and the Aspect of the Cougar can help you chase fleeing enemies.

Nidalee is very good at escaping from enemies in the jungle due to her passive Prowl combined with Pounce and Flash.

Nidalee relies on being able to heal constantly so that she can return to fights or escape. Using Ignite on her is an effective way to keep her from returning to a fight or killing her if she tries to run.
Nidalee is very susceptible to hard CC and does not have any of her own. Crowd controling her as soon as she comes into range of your team can get her killed very quickly. Due to her synergy with Guinsoo's Rageblade, hard CCs can also greatly lower her effectiveness.
If you are chasing Nidalee and you are both at low health, it is highly advised not to follow her into brush. This is a chance for her to change form and heal, reversing the tide of the battle.
If you are having trouble dodging Nidalee's Javelin Toss or need to take a hit for a teammate always remember that it does more damage based on the distance it has traveled between it and her. If you close that distance, it will do less damage.
Javelin Toss can be easily dodged by side stepping or standing behind minions.
Nidalee has great mobility and is good at baiting team fights in her team's favor by pulling unwary enemies into bad positions. If you see a Nidalee leading you or your team through the jungle or any other tightly spaced areas, don't follow her unless you have good knowledge of the area via wards or some other form of map awareness. It also leaves yourself open to a powerful Javelin Toss that could kill you.