1) If the preview image you submit for the gallery is any of the following, the gallery will be rejected:
Not softcore (all preview images must be softcore, this includes no nudity, see the main page for examples of acceptible preview images)
Low quality. (I want really really high quality, so, I recommend you upload the preview rather than use the auto cropping tool which I have found kind of sucks)
Does not match the submitted gallery
2) If you submit to the wrong category (Submit only to the "0 0 HOSTED GALLERIES" category or I'll never see it. It is the second category listed so it shouldn't be hard to find.
Remember that all galleries are listed based on productivity. So, good preview image, means more traffic.
3) The gallery must have my affiliate code, obviously.
You can submit as many galleries as you like. In fact I'd love to see hundreds. Just remember MOVIES ONLY. Also, please fill in keywords, especially Pornstar names.