What to build really depends on what you want to do.......

If you want to hit Lv10 NPCs, then focus on archers....
If you need more farm teams to hit Lv5 NPCs, focus on ballista and transporters...
If you're far away from RED banners, but want to help your alliance... focus on scouts for scout bombs.... they can be sent effectively from long distances...

If you don't know wtf you're doing - Prodigy left a decent game plan....

Phew Phew - agreed!