Blitzcrank is a easy champ who makes really fun, and in my opinion the strongest supporter in the game.
I played that build so many times and never loose.
You are on of the srongest late game chars with that build.
You have a lot of attackdmg, life, ability, amor and magic resistance.
That technique is based on manamune. Also your passiv becomes your ultimate weapon and its perfekt to shoot a fight because you have the surprise effect on your side.

in the early game as supporter use w to quickly get up to the enemy and knock him down with s. If he want to escape you get him back with q and the ad carry gets feed.

[pros]
- easy and strong invade
-pasive will safe you life so many times
-fast escape
-strong with ad and ap
-no cooldown on the ultimate
[/cons]
q have long cooldown