heres my 2 cents
from tgp owners point of view
original good quality content
(not necessarily exclusive - just stuff i havent seen a ton of times)
original fast loading gallery design
good accurate description
content fits category
nice quality thumbs
fast server
from submitters point of view
#1 - good converting paysite tour
content that makes them want to click to the sponsor for more like this - but wont quite get them to cream their jeans. even if they dont join right then they may recognize my gallery template and content quality and join if they click my next gallery
a few bad things would be
sponsor provided content that tgp owner has seen 100 times.
low quality sponsor provided screen caps (ive had a gallery submitted to my tgp that had a fuzzy out of focus screen shot of the arm of a chair and part of a foot... i got a laugh out of it that day, but some days its reason enough for me to hit the blacklist button. if the submitter wont take the time to at least examine the content on the gallery im not going to waste my time reviewing it)
not giving an accurate description, lieing on your description or a description that makes no sense. for my tgp i want a good and accurate "DESCRIPTION" of what is happening in the pics or vids. not a sales pitch, not a riddle, not a lie, just tell the surfer what the gallery is of.
thats all i can think of. basically, good content and a good paysite tour. and then all the other stuff i said
lol