Upgrading...

Start with Research Lab, then move to splash damage defenses (mortar, wizard). Then cannons, archers, tesla, air defense. Will upgrading the corner or intersections of walls. But stagger your builders, try to upgrade 1-3 defenses at a time, never more. 1 of each defense at a time, (ex. mortar and cannon on day 1) then other builders can work on camps or barracks. Always do storages and pumps last. Try to max upgrade before moving to next TH.