Recip links is required, no one will get listed if no approved recip links found on the gallerie(s)... Make sure you using correct recip every time you submit... so for every category use personal recip links thats important
Make sure thumbnail you made fits quality and categories you submiting to, its up to you, to be honest then better your thumb then more hits and selles you will get, make sure thumbnail are most hot from whole gallery content.