Hello, this is my first guide here so please give feedback and comment on my build.

Skills:
-Max Impure Shots first
-Max Double Up Next
-Put Bullet Time whenever possible
-Have Make it Rain a level 1 at level 4 and max it last

Steps to Playing a Aggressive/Powerful Missfortune:

*First of all you would want to grab yourself a Dorans Blade, If you think Doran Shield is better, go with it
*You should be constantly harassing while taking minimum damage, use your Double Up whenever possible and also playing safe(flash and ghost)
*Last hitting creeps should be able to give you enough money to get another dorans blade and boots(I usually have enough for a B.F Sword)
*If their team has not little to no CC/AP, then you should get a bf sword before finishing the merc tread
*I.E(infinity edge) is a core item for mf which is needed as early as possible
*after getting I.E, I'd suggest buying catalyst due to the lack of hp and mana
*without finishing bansees, i would then get last whisper for the armor pen.
*Finish bansees
*now is the time where you start getting lifesteal and build your damage by getting a bloodthirster
*Depending on the enemy team, a hexdrinker/Madred Bloodrazer/wits end would be a good choice

Pros and Cons

-Amazing harassment early game with 2 dorans blade and have decent hp
-being able to deal good damage with high survivability
-pretty cheap and effective

Cons:
-may not have alot of attack speed(W skill comes in play)
-not have as much damage late game

Alternatives:
-Hexdrinker-For CC team
-Madreds- Tanky Team
-Bloodthirster-Non Tank/Squishy