How do you farm resource tiles efficiently in Dragonfire?

Good tile farming means yield without damage. The method:

1. Identify the resource you're short on (look at which building or recruitment is blocked).
2. Pick a tile level your army clears cleanly, without heavy losses. Farming level 6 on repeat beats failing at level 12.
3. Below level 10, read the defender's type and play the counter plus green dragons.
4. Chain your marches: while one army harvests, send another to a neighbouring square.
5. Take the Swift Stride research (+3.5%/level march speed) to cut the round trips.

The classic trap is aiming too high. A tile that's expensive in losses costs you more in retraining than it returns. Aim for the highest level you clear painlessly.