Once the parts are clean, lay them out on a clean background for your photos. I usually go to the local drugstore and pick up a few sheets of black or white construction paper. Whatever color you select, you want to ensure that your parts stand out. Also, be sure that you haven't included any additional parts in the picture unless they go with the specific item you're selling. You don't want anything to clutter up your pictures, nor do you want people to think they're getting a "free gift with purchase." When it comes to the photos, imagine yourself as a potential buyer when you're taking the pictures. What sort of pictures would you find most appealing?
 This is how you want the pictures...  This is how you want the pictures of your parts to look when you're trying to sell them. A clean and uncluttered background makes the parts stand out. |  This is the perfect example...  This is the perfect example of what not to do. By leaving the exhaust pipe, A-arm (even the shoe) some potential buyers think that what they see in the picture is what they're getting regardless of description. | |
The next, and possibly most important step in selling your parts on the Internet, is your description. Tell it like it is. If the paint is chipped off or there are dings in parts like pipes and A-arms, let the buyers know. They know they're looking at used parts. Not everyone is expecting a part in showroom condition. There's nothing worse than having to deal with a disgruntled customer who feels they've been wronged. This will only generate more work for you in the end.
Now that you're ready to start selling, pull up a comfy chair in front of the computer and take your time. Once you enter your description and post your pictures, double-check everything before you post your listing. If you made a mistake, correct it before posting the ad. Be sure to post your listings in the evenings. You want people to be home and unoccupied, allowing them plenty of time to peruse and/or purchase your items. Another helpful tip is to prepackage your items for shipping. In the event someone asks you how much shipping will cost, you'll already know what size box you'll be using and how much it will weigh when you go to calculate it. That could save you a ton of time.
Once you finish submitting your listings, sit back and answer questions when they come in. In no time, you will see how much your not-so-hard work pays off. You will gain garage space as the parts start to disappear and the dollars start to flow back into your pocket.
Now, if you find yourself staring at a dozen spare parts but don't have the time to sell them all, don't freak out. There are numerous companies that will handle everything for you. They'll even take the pictures and ship your items for a percentage of the profit. You don't get as much on your return, but you do save time and still get to fill your pockets with a little extra dough.
So the ball is in your court now. Whichever method you choose, you'll score some cash on your used items and free up some room in your garage. Hey, maybe you can use that space to store your new toys! The possibilities are endless!