Blitzcrank, early games a bit weak but he makes up for it with good cc, mobility, and easy ganks. Basically he's going to be a second Support/Tank which really helps your team with getting picks and in teamfights if you have a strong AP carry and AD carry. Your goal shouldn't be to get kills but to help your bot and mid lane as much as possible, although the early gank top isn't a bad idea to snowball their lane.

I usually tank classic, top lane or support runes. It helps get through the early game.

Usually take tank masteries, I really like Bond of Stone, since you are a tank
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There are two different builds against AP and AD threats. A lot of situational items, use at your discretion. Generally you want to build tank so you can ditch out a lot of damage early game because of your base damage of your abilities and stats and then be used as cc late game.

Max your Q since that's your main CC that you need on a short of a cool down as possible, and W next for mobility.

Classic Jungle spells. Ghost can be used sometime, although not recommended.

Pros: Good peel, take the carries.
Cons: None

Ganking Method 1: Use your w to catch up with your target and use your E to knockup then ult for the silence. Then if they try to get away pull them.
Ganking Method 2: Q and then E then R.