I'm new to guide building but I feel Swain is rather underrated in Dominion, as I've been playing him a lot I felt we should have a guide out for him. This may not be anything solid but it's how I've been doing it and seems to work.

Anyway let me know what you think or ways this could be improved, again first time setting this up and I'm still fairly new to it.

-Promote is very handy in Dominion when trying to push to a tower.

-Garrison is great for times when the enemy is turret diving you to try and capture and has saved me on more than one occasion.

Most matches I don't get to buy the whole set, usually make it to Rylai's and game is finished before I get more. However this build gives a good amount of HP and damage output.
I have been able to defend a tower against two opponents on several occasions and come out with half life still.

Pros:

High HP
Great damage output
Survivability
Great defender and attacker
Good CC

Cons:

Not great at bottom lane do to shorter range attacks
A little slow 1v1 with damage at start but not bad
Not as fast as some other Champs
A fight against a real tanky Champ may not win but you can CC and run