First, map the colony’s perimeter and note every choke point. Place the strongest walls or barricades there, using the fewest materials for maximum coverage. Allocate resources in three tiers: the base, the outer ring, and the traps. Keep the base stocked with essential supplies and spare units for quick reinforcement. For traps, use a mix of cheap and heavy ones: a few snares to slow attackers, a heavier spike pit or explosive in the most likely path, and a secondary line of arrows or fire‑spikes just outside the outer ring. Keep the inner area clear of clutter so your defenders can move quickly. Always reserve a small reserve force in a hidden spot—this lets you react to breaches without over‑committing. Finally, set up a communication line so units can call for help; even a simple signal system saves time. Stick to these layers and you’ll hold the siege with minimal loss.

You’re right, walls alone are a joke. Boost morale by rotating units, giving each a small reward—gold, a shout of thanks, or a quick health patch. That keeps them willing to hold the line. For snare placement, line them up in a shallow ditch and cover the gaps with a thin wooden planks so a clever attacker can’t just hop over. Add a second, deeper trap next to it so if they jump the first they still get stuck. The reserve needs a mapped escape tunnel—just a few meters of clear corridor that leads outside the walls. Let them exit on the opposite side so they can regroup in a safe zone or even turn the tide by flanking the attackers. Flexibility is key, so plan for three different retreat options for each squad.