Do not be afraid to push yourself on other people when selling firearms or anything else online. If people do not know you are selling items, how can they buy from you?
So throw plugs in every once and a while. Create a myspace account for your selling account, post the item you have for sale on facebook, link to it from craigslist (Craigslist doesn't allow for people to post guns... so say that you are adhering to all their rules and link to your gunsamerica listing or something to that affect). Whenever you are in a forum (specifically a gun forum) tell people in your signature that you are selling stuff and (if policy allows) link to your items. Blog about your items in your personal blog. Create traffic any way you can. The more people you have viewing the listings on your site, the more likely you will sell more items.
Now, some people may be wondering why I haven't been pushing my items for sale on anyone. Well currently I am building awareness of this new username, and I am trying to keep this blog focused on the point. I have items for sale under other usernames and use my own formula for those names, but I want to keep this separate. I am however pushing this blog using these tactics.