If it draws hard no matter what battery you try it on, then you'll know for sure it is the atomizer. Valgar is right, alignment of the holes is critical, but also check to see if the atomizer holes are clogged. Do a search in the forums for cleaning techniques, there are entire threads devoted to this topic.
If it works on other
batteries but just not the current one, then it is probably a stuck, or "sticky" switch. I had this problem with one of my
batteries and tapping it lightly seemed to help a little. It wasn't good enough for me though so I went poking around inside it and decided to widen out the hole to ease the draw. I started to notice improvements but got greedy, went too far, and bricked my battery 8-o ! I let all the smoke out of it.

If you accidentally short these puppies out they get
real hot real fast. Luckily I have 3 more so it's no big loss. Now I've got parts to play with.
Good Luck! Vape On!