The cannons theme comes from Ship's Cannon, Cannon Barrage and Knife Juggler (a cannon in spirit). This is supported by minions that summon other minions. Conceal is used to make it hard for an opponent to disrupt your board once you have it set up.

Mulligan for Ship's Cannon, Mechwarper, Hungry Crab, Golakka Crawler and Conceal. Since there are so many cheap minions in the deck, you can mulligan pretty hard for those even if you are offered a good curve in your initial hand.

Jar Dealer and Haunted Creeper are not too risky to play on an empty board. Other than that, be careful to play minions too soon, unless you think you have more Crabs and Crawlers in your hand than your opponent. If your opponent isn't playing anything threatening, it's fine to not commit your important minions to the board until you can make a big Mechwarper/Cannon/Conceal play (or 2 out of those 3).

If you have Patches the Pirate, you can throw him in there too.