1. Focus your camera
In order to ensure your images are sharp, make sure you know how to focus your camera. Digital cameras with autofocus are often difficult to focus precisely, especially when shooting small objects. Make sure your read your owner's manual and understand how your camera's autofocus operates.
Most digital cameras are designed to easily focus on large objects but have difficulty on small objects. It is often useful to put your camera in spot focus mode. Spot focus will give you more control over what part of a scene the camera is actually focusing on.
2. Use a tripod
Even the slightest movement while taking a picture will cause motion blur. The closer you get to an object the more obvious the motion blur becomes. Using an inexpensive tripod will make a big difference in the sharpness of your images.
For really sharp images it makes sense to invest in a good, sturdy tripod. If your camera has a remote shutter release then use it, if not then use the camera's built-in timer to minimize camera shake.
3. Put your camera in aperture priority mode
To get the largest area of your subject in focus, it is good to set your camera in aperture priority mode and set the aperture to the highest number possible. The closer you get to your subject, the more important this becomes.
4. Use soft lighting
Your camera's built-in flash will rarely give good results for product photography. For soft lighting either shoot outside on an overcast day or use a light tent like the EZcube, Cubelite, or use a softbox.
5. Use image-editing software
Even inexpensive software like Photoshop Elements or ACDSee Photo Studio can make your product photography much easier. It may seem like it's faster to use an image exactly as it was shot. But in reality, it is difficult to shoot an image precisely how you would like to appear in its final form. Image editing software allows you to crop an image, adjust it's exposure, sharpen the image and then resize it, often in less than 60 seconds.
Why the difference?
The biggest difference between an amateur's product snapshot and a professional's product image are sharpness and lighting. Steps 1,2, and 3 will improve the sharpness of your images while Step 4 will improve your lighting. A minute spent editing an image will improve it further.
Because these few steps seem so basic, it's tempting to ignore them. However, if you take time to follow them, you will see a huge improvement in the quality of your photos