First of all, thanks for your service and keeping us safe..
Next, you might want to try starting out just selling things that you have laying around your place that you don't use anymore. It also helps to have an interest in what you are selling as it helps answer questions that your customers might have about the item you are selling.
Also by starting out selling things that you just have and don't use anymore will let you get a feel about how ebay auctions work and gain a bit of experience before you jump in with both feet. Too it will get you some feedback built up so that your future customers will have a bit more confidence in buying from you.
I myself started out selling all of my old video games that I no longer played, plus some dvd movies that I no longer watched. Things like this sell well and will help you understand how things work and get experience in listing your auction items and how to price, ship and things like that.
Just about any and everything sells on ebay. One good way to get some idea about what you might want to sell would be to browse through the 'completed listings' catagories on ebay and you will probably find something that you might want to get involved with. The completed listings will list everything that has sold or not sold in it's particular catagory,,for instant: video games, dvd's, clothing and accessories etc..
Just go to the homepage and click on 'sitemap' at the top of the page. Once you get on the sitemap page look in the first column about halfway down and you will see a heading 'completed listings', just click on that and then you can start clicking on different catagories and browsing through the many items and see if anything interest you...
If you do find a product that you think you might want to sell, then browse through the completed auctions for that particular item and take note about how the seller went about listing it. Notice things like how they described the item, how they listed their title, what type of shipping they offered, what types and colors of fonts they used and things like that. Doing this will give you a heads up when you get ready to do your first auction..
The best thing I can tell you is to 'just do it'. once you actually start listing and selling a few things you will gain experience and learn from both your mistakes and successes. Don't worry if you don't really make a huge profit on your first listings,,you will learn, and that is most improtant..
Also on the sitemap page there will be heading for just about everything you need to know, so click on them and read through them..There are 'selling tuitorials' that will walk you through the steps to help you get your first listing completed..
If you need any advice or run into any problems just PM me and I will be glad to help you out...