These are all good tips. a good photo editing software that takes some getting used to but takes you further than any basic photo editing software is GIMP. It's like photoshop, but it's free, just google it.
Here's what I do. Since I don't have a soft box I setup my own studio. I have three big windows facing south along one side of my dining room. I wait until sundown or sunup and set the blinds so that I still get a good amount of light through the windows, but yet I am not letting beams of light through the blinds. My platform is the kitchen table, and I use a black or white (or whatever else) sheet as a background. I lay the sheet on the table, with boxes stacked up high at the end of the table (or big stiff posters) and drape the sheet over them to white out the background to take away any distractions. I use the chandalier as an above or "boom" light (in pro photography terms), then I get a garage plug in light with the clamp and the metal bell around the bulb and get a piece of white cloth to cover over it (this softens up the light a bit). I set that off to the left of the "set", in front of the camera. this serves as another fill light. I then might get a tall lamp with a removable shade and a high light output, and unscrew the lampshade and lay it on it's side, draping over the bulb and the metal support, so it gives the light some direction rather than just "up". (you can also do this with a metal shop light but many lamps have adjustable brightness so you have more control over your lighting) this serves as my main light, giving you somewhat of a studio setup. Place this light next to you or right behind you. Now, you have a "poor man's studio". feel free to toy with the lights to how you see fit. Now, camera choice is important. I have a canon DSLR camera that I run manually (ISO, Shutter Speed, ect...) this allows me to have full control over the lighting of the set without using flash (which I HATE) I set this on a tripod. if you have a basic point and shoot camera, I would turn the flash off and set the camera on a tripod and have a countdown timer in place so you have as little of a chance to have a blurry photo. But, going with this option, you have to have more control over your lighting in the studio, control which this poor mans setup lacks. If you have a DSLR but don't know how to run the camera manually, set it to auto or whatever works best for the setting and go ahead. but this makes you camera more like a standard point and shoot. my advice- turn flash OFF!
hope I helped
also, I tend to use things like holsters or a small block to prop up your gun. NO pens through the trigger guard. It just looks tacky. Something like a small leather wallet that can hide behind your gun when you are shooting is fine. THEN, use props. have magazines, ammo, knives, holsters, belts, military junk, whatever else.
also, with guns, a softer light tends to work better due to the reflective or hard surface of the gun.