Critwick is a very OP champion once you hit level 6. Before level 6, you still cannot 1v1 very many other people. You are not criting as much or doing much damage when you do crit, in the begining. At the end of the game, you can 1v1 or 1v2 almost anyone in the game. This build basically makes you a tryndamre with the passive of lifesteal. The extra lifesteal is to make you able to solo baron and 1v2 or 1v3.your W is the most important when fighting someone to pump out that crit more.

The runes that were picked was to make you attack faster and crit more damage in the overall gaming. These runes also go well with Trynd. The attack speed is mostly just for the begining of the match so you can farm faster and harass a little bit more. The crit damage is for when you crit, you do more damage than what you would have originally done without them.

The 1st ability i recomend u get 1st is your Q. I am not telling you a build for jungling, this is a build for a lanewick critwick. The Q alows you to get the last minion hit and to harass people in the lane. Be careful of your mana for it does suck of most of the mana. After that get your W. you do not need your E until late in the game when it is most needed. Max out W 1st but get Q 1st in game. Max out Q second then E.

Pros: Super OP. Take out anyone in about 3-4 hits
Allows you to solo baron while team is defending/pushing

Cons: Hard to master
A quite expensive build to make