Just a few general tips and tricks to master the game.
The trick to success in Tiny Battle Simulator is to recruit as many soldiers as possible in the early game. Losing soldiers in battle will bite you in the backend in the mid/late game.
Use save games or the auto save slot to retry battles if you lost soldiers.
Only fight if your squad has more soldiers than the enemy.
Make sure your recruits have weapons with long enough range. If they stand in the second line they might not reach the enemy. If they only have a knife or short range weapons, put them on the front line!
Ranged units can attack the enemy from a distance. Make sure they can attack from the start and make sure to protect them. That way you can give your good armor to the front troops.