Play as Axel.

Well, the main army is obviously the Knights of Isabel. At the beginning, I try to upgrade the archers to Alt-Archers, along with the knights (who have shields and protect the archers from ranged attacks). This is a pretty good combination for clearing out neutral creatures, but there's a big downside – you'll be short on ore (20 units per upgrade for both buildings). So, at first, you focus on Alt-Archers, and always have knights with shields nearby, and you assign one peasant to each and attack the neutral creatures. Then, you switch to knights and train them in large numbers. The skills depend on your preferences; for me, it's attack, luck, light, logistics, and training.
P.S. I play more as the Academy.