If you plan to sell items on eBay or any other sales site or app, you want your items to look their best.
Generally, photographing an item for sale is pretty much like photographing anything else. You want to make sure that your subject is toward the center of frame, lit well without washing it out, and with as little background noise as possible. When doing artistic photos, you always want to apply the “rule of thirds” where you imagine a nine-box grid over your subject and place the focus of the photo where the gridlines intersect. When photographing an item for sale, it is better to place your item directly in the center of the photo. It might make for a visually boring photo, but it also puts your item front and center, which is where you want it.
How you actually photograph your item comes down to how large the item is. For a small item, you can either place the item on a surface with a solid color that provides high contrast to the color of the item (a black background for a light item, or a white background for a dark item), or invest in a photo studio in a box like this one:
This particular item costs about $110, and includes the box, the tripod and lights. It’s about 20 inches on a side, and the sides work to diffuse and soften the light. If you’re using a home setup, you want to use a direct light (in some cases, commercially available flashlights work well), but you’ll want to put a white or pink sheet over the light to prevent “hot spots” on your image.
The same general rules apply to a larger item. I have had great success with hanging a solid colored sheet behind the item to eliminate background noise and highlight your item. Alternately, a portable photo studio like this one can be used.
This particular unit is about $200 online, and is designed for Chromakey, which is used in special effects so that a new background can be edited in with no artifacts (you’ve seen this in action if you ever watch the weather on TV), but the green is also great for very light or very dark items.
As far as formatting your image for Ebay goes, their size requirements say that you want your photo at least 500 pixels on the largest side so that it’s nice and clear. The maximum size of the image doesn’t really matter because Ebay has an image compression algorithm that will reduce the size of your image without killing the detail.
I hope that this helps!