Stronghold Crusader 2 combines castle building with real-time combat in a harsh desert setting. Surviving the AI lords requires a stable economy just as much as strong walls.
Water is precious in the desert. Build near oases where possible, place granaries close to your keep and diversify food sources. Keeping popularity high with steady rations and low taxes prevents peasants from leaving.
Use multiple wall rings and place archers on towers to cover approach routes. Gatehouses, moats and traps slow enemy siege units long enough for your ranged troops to thin their ranks.
Sandstorms, locust swarms and fires can cripple an unprepared settlement. Spread out key buildings and keep stockpiles in reserve so a single event does not stall your entire economy.
Once resources flow steadily, train a mixed army of spearmen, crossbowmen and siege engines. Combined arms work far better than mass-producing a single unit type, especially against well-fortified enemy lords.