I've done a couple of things recently that have really helped me sell my gear.
The first is building my own website to showcase a large collection of electric, acoustic, jazz and bass guitars I'm selling. I'm no SEO wiz, but the site seems to be working. I get enquiries from legit buyers every day, and I'm selling a very nice Gibson ES-175 Steve Howe Signature (2006) this weekend for my asking price. My prices are competitive, in part, because I don't have to pay extra fees for eBay or Reverb.
The second strategy is taking many of my instruments, including some fine ones, to the guitar shop of a friend of mine. He's also a great luthier, so he gives all my guitars a once over (and performs minor fixes) before he puts one up on his wall, and he carefully monitors anyone who wants to play an instrument. For these nice services, and for displaying my guitars in his well-trafficked shop, I pay him 20% on each of my sales. I've sold 10 instruments with him over the last couple of months and everything has gone smoothly.
In this second scenario, I'm still coming out ahead when compared to the auction fees, massive shipping charges, and the general headache of Joe Q public on the auction sites.
Just a couple of strategies to consider.