Before we start i want to say that this is my first guide and i will try to keep it updated
so i apologize for any mistakes :)

Blitzcrank is my favorite champion in the game, he is fun to play and that feeling when you get a grab is nice, Blitzcrank's job is to get the enemy adc by grabbing him and him out of his safe point, at early game you are strong so u have make the most of it

Nothing special about these runes just basic tank runes, you can exchange health or some armor for more utility buts thats how i prefer it.

The masteries might be the strange since im running no defence and why i have my offense on ad not ap.
First Offense
CDR is needed for blitzcrank no problem in that.

Double edged sword : youre going to build tank the extra 1 damage will not be a problme plus you will be dealing extra and as a tank you will need it.

AD : again youre building tank and you will need extra damage and your E will utilize that the best with its double ad scaling running ap is useless as you will not be getting any extra making it not add much damage to your kit

Defense : I have no points in defense because running tank runes and the fact that you dont need it as much but you can still go 0/9/21 if you think you need it

Utility :

Blitzcrank is mana hungry early game and you need extra movment speed to get grabs
COOKIES
Since you're a support you wont be getting much gold especially if not getting any kills so the extra gold is pretty nice
Again CDR you need it