Ok! so I finally have a set build for kha'zix. I developed this build in pvp, its mainly to amplify Khaz's damage as well as give him a little more survivability (which he may or may not need depending on how well you use "Leap" and "Aoid Assault". So I am creating this guide on a few things I do to make Kha'zix an assassin to be feared...

[Pros]
-Massive Damage to any Champion unfortunate enough to be caught alone

-Q - Taste Their Fear being Khaz's strongest skill has a very low cool down

-Great ganking ability due to his passive E and R skills

-Able to escape Fight very easily due to E and R as well

-His Passive makes ambushes particularly deadly due to slowing enemy champs on regular attack

[Cons]
-early game killing power is very low (till at least Level 4)

-is very squishy (starts with 18 armor)

-untill equiped with cool down gear it can become difficult to escape at times using "Leap" (cd is around 20 seconds early on)

-burns mana extremely fast, especially when fighting enemy champions

[Exhaust]

I choose exhaust mainly because of Kha'Zix's armor. Exhaust for 2.5 seconds makes your enemy extremely vulnerable and will allow you to attack and hopefully kill any champion you come across.

Flash

I also use flash, pretty much in the same way everyone else uses it. As an escape when you are in danger, or to chase an enemy champion as they try to escape.

Now on to the killing, a few tips I can offer when using Kha'Zix are...

-Be Cautious and Patient, wait for your target(s) to be past the middle of the lane to avoid losing them close to their turret

-Look for Champions that are alone, they are extremely vulnerable to Kha'Zix and your Q and E skills will allow you to make short work of them.

-Always make sure your passive is active before starting a fight, the slowing attack is very helpful

-if you are stunned...run... unless you are 100% sure you can take them (remember to use flash or exhaust)

-the champion that strikes first..also strikes last (usually). Leading off with Taste Their Fear & Leap (evolved or not) is a great way to start a fight.

-Void Assault is just as good mid fight as it is to start or escape from one. They cant hit what they cant see...

-in team fights, watch those already weak a few well placed Q attacks will easily help push the enemy team back, and hopefully a few will run off alone...but remember they will be looking for you in the mayhem( khaz is often targeted and killed first in team fights). Void Assault is very useful in these situations...

-Lastly, keep your movements hidden. you are at an advantage if they enemy team cant keep track of you (moving between lanes for ganking often, remaining in grass, etc...)
I have found it particularly effective when assisting an ally in pushing a lane to hide in grass, wait for the enemy to assume your ally is alone and the second they push back...ambush them.

-another good idea is to hang around the tank, High dps, another assassin or an ally champion (that doesn't mean just Ks them) that can reel/stun very well ( like Blitzcrank, Ashe, Veigar, or Evelyn to name a few) pairing yourself with a tank allows you to avoid damage and take on more enemies at once, while having someone who can stun,dps,or chase well allows you and your team to stock up more kills a lot easier.

-lastly... don't allow a rengar to kill you. instead kill him at lvl 17 for a fourth evolution point (or so I've heard)

Now on to evolutions...

Firstly, I always Chose to evolve Claws (Taste Their Fear)
the amplified damage and range of the skill & his regular attacks will be your main source of damage(Increases damage to isolated targets by 12% of their missing health).

Secondly, Wings (Leap) quite simply because the masive range increase is very useful in chasing, and escaping from fights. You can also jump over walls...

Lastly (or is it), would be a choice between Spikes and Active camouflage. this is really up to you and if you prefer the stopping power of the evolved Void Spike (Void Spike fires three spikes in a cone. Void Spike will consume Unseen Threat to slow and damage all enemies struck.) or the enhanced Void Assault (Void Assault can be cast three times. Kha'Zix takes 40% reduced damage while in stealth.)

this is my first build, so if you have any comments or (constructive) critisim or suggestions on how to improve my build, id be glad to hear it. sorry if i got a little wordy XD

hope to see you on the field of battle, Enemy or Ally...

Lux Canis

(no...I don't use lux...)