You asked...
Good start. It is worth your time to stay at it and learn what you can here.
Learning to take great pictures increases the selling value of your knives by quite a bit. 20% maybe.
Fuzzy, blurry pictures of a knife set on an old stump outside with your feet in the picture don't help. I always feel sorry for those guys trying to sell a knife with a crap picture. They will never get what the knife is worth.
Lighting is 80% of a decent picture. If you don't light it right it, the best software work won't make it a good shot. I agree completely with John E above, the lighting is a bit flat in your picture. Try 2/3's front light, 1/3 behind or other spot lighting. Spend an hour taking pictures with different light sources moved around. Look for shadows that contrast each other unnaturally, look for harsh unwanted reflections and try to eliminate them. The best time I ever spent on learning how to take decent pictures was around not being lazy with the lighting. Once it is setup where you like it, expect to have to move it again. Knives have different shapes and the lights will need to be adjusted.
Look for daylight balanced light bulbs. Something in the 5500 to 5700 Kelvin light range. Several of your images have typical tungsten red color to them, one has a cool blue tint that has some fluorescent tint to it.
If your camera has the ability, learn how to adjust the white balance in your camera. It's a bit dry and technical but it is fairly easy to do and the colors in your image will be a lot more accurate. This really helps and it is really simple to do. If you set a color balance in your camera, don't forget to check it and also keep the lights the same in the room you are shooting so the camera knows what to expect.
Some cameras allow tethering. This means hooking up a USB cable to your computer to the camera. In a tethered set up you shoot a picture and it shows up full size on your computer screen instantly. Shooting tethered will dramatically improve your pictures by being able to see what is going on instantly rather than trying to fix issues in software processing.
I have taken literally thousands of "commercial" product images and I would not even consider shooting products or a knife with out using a tethered set up and multiple lights in some kind of light tent. It's a requirement of my business. I have to take pictures every week that affect my income. I can't post blurry, crummy pictures and expect to sell anything on my supply site. Samantha is my graphics person now and she takes most of our pictures lately. I reject nearly every picture she throws at me until the lighting, the focus, the positioning and depth of field is where I want it. Good pictures = money. Knife makers really really need to understand this better.
I am a Canon camera guy simply because that is how I started and I have a large investment in lenses right now. Nikon is also as good. You can pick up an excellent used SLR in either Canon Rebel line or the Nikon Dxxx line for $200 to $400 bucks. You will be able to set up tethered shots and really up your game. If I was buying new today to get into a "good" camera, I would look at the Canon Rebel 2t or 3t. The 4t just came out and I don't know anything about it. Nikon has a model positioned against each of these Canon models and these are equally as good.
Take a look at composition of some of the pro's taking knife pictures now. Coop's pictures have a certain look to them that you can spot across the room. He has a style of lighting and photoshop work with consistent composition. Buddy Thomason(sp?) experiments with background and composition more than Coop but has as good a technical presentation as Coop. They work together often so you will some similarities in their images. Buddy gets more artistic freedom to experiment as it is a hobby for him and not his profession. His pictures are better than most professional though. Point 7 also has a style you can generally recognize after some study. There are several others out there that put out high quality images. Some time spent browsing their galleries will make a difference in how you compose a shot. I want to be delicate here. There are some professional knife photographers out there charging for images that are less than flattering. Every pro taken knife picture is not great. Fortunately this isn't all that common. I had Coop takes a lot of pictures for me earlier before I started to study photography and I am glad I did. He inspired me to learn photography and up my game.
One last thing and I will get off my soap box. I apologize if I sound preachy. You asked for constructive input and I am trying to give you that...
Go to the home store and buy a 1/2 dozen ceramic floor tiles. I have around 20 or more and use them in every single picture I take. Get a couple that are uniform gray and then others with colors, patterns, etc. Also if you can, get an old wallpaper sample book. You can have hundreds of cool back grounds for your knives.
Keep posting images. I'd like to see how it goes for you...
