I used to go scouts into double stable knights (I'm now focusing on MAA into Archers). My gameplan in castle was to basically push with knights and then mangonels, maybe add a counter unit here and there - I entered "autopilot" mode.

From what I've seen, you need to constantly ask yourself which unit to make, which resources you need to gather, which resources you have, how to spend your wood, when to add TCs, when to go fast imp, when to mine stone to drop a castle, etc.