First, it is recommended that you have an armory. Continuously build troops in all or atleast most of your castles. Choose one castle (not your capital) to dump your excess troops into in order to stay out of the red at all others. This will mean that your armory is severely in the red and you should never march from it (with one exception to follow in the next segment). However, after losing a big battle u can easily refuel your lost troops from this armory and, without much delay, continue marching on targets. This will also allow u to swap out cats or cav if u need to switch up strategies for a certain target.