Bring them down with artillery and manpower! Ramp up your sites with [[Landmass]], [[Frontier Settlers]], and [[Land Surveyor]].

Use [[Gnome Hollows]], [[Great Wall]], [[Mountain Pass]], and [[Perilous Bridge]] to create roadblocks to slow/prevent your opponent advancing into your territory.

18 of your sites can create a token on entry. Combine this with [[Necromancer]] for a steady stream of recruits. Once you've established several sites across the middle of the board, leverage [[Border Militia]] and [[Raise Militia]] to gain large chunks of tokens.

Use those tokens, along with any leftover Frontier Settlers and Land Surveyors, to man the [[Siege Ballista]], [[Corpse Catapult]], and [[Payload Trebuchet]]. For the Trebuchet, throw [[I Am Colossus!]], [[Midland Army]], & [[Craterize]] for massive early damage or to secure Death's Door. Or play them if drawn later, this deck ramps rather quickly. The Catapult gives each dead minion a second use as extra damage.

An additional ranged package, for supplemental damage and control, includes [[Belmotte Longbowmen]], [[Yourke Crossbowmen]], [[Hunting Party]], and [[Vantage Hills]].

Protect your fragile army with [[Bailey]] & [[Shield Maidens]]. A copy of [[Tragedy Worrywart]] can also prove crucial against magic-damage control decks.

Sometimes you won't draw any artillery, or you'll need to rush in and damage sites/minions. [[House Arn Bannerman]] and [[Drums of Doom]] turn your weak tokens into threats. Drums also turns anything fired with Ballistas, Trebuchets, and Catapults into a lethal shot (if nearby). [[Belfry]] allows full repositioning/attacking while keeping your defenses up.

Three copies of [[Bury]] is your non-combat removal package.

[[Common Sense]] lets you search up removal (Bury), token makers (Border Militia / Raise Militia), ramp (Landmass, Land Surveyor), or ranged support (Belmotte Longbowmen).

[[Call to War]] provides additional toolboxing, searching up ramp (Frontier Settlers), protection (Shield Maidens / Tragedy Worrywart), power boosts (House Arn Bannerman), or ranged support (Yourke Crossbowmen / Hunting Party).

The deck splashes (A) for [[Raise Militia]], which only requires a single threshold. With 1/5 of your sites providing (A), you should end up with 1 or 2 during the course of the game. If not, throw any held copies of Raise Militia with Trebuchet.

I've also thrown in [[Returned King]] and [[Pnakotic Manuscript]] since I own them, but haven't been able to draw either of them during a game yet, so your mileage may vary.

Siege Warfare

@AllTheSheep