I found that if you raid hard, you don't need to upgrade your collectors till you are maxed th8, this leaves your builders free to upgrade more important things like defenses/barb king. Also th7-8 get your air defense up asap as it will help heaps in defending against dragon bombs in war.
Try and max out everything for your th level including walls bar collectors before upgrading town hall or it will take way longer playing catch up than you think.
For you guys, th8 and up don't bother upgrading dragons to level 3+ do them last, work on your raiding troops first(barbs and archers) then do your golems, pekkas, wizzards and so forth. Will help heaps in the long run.