This is my first TW also. I micro-manage everything in the strategy part, and fight 80-90% of my own battles.

On the occasions that I allow the battle to be auto-resolved, I do so because I want to take a settlement for minimal losses. For some reason, the auto-resolve appears to be able to make the enemy abandon their settlement - shortening the campaign - whereas I always seem to have to fight to virtually the last man. Thus I take more casualties, whilst also inflicting more casualties on the enemy and leaving fewer forces to come back and fight another day. Perhaps I'm missing a trick when fighting my own battles.