Lighting your artwork
It is best to photograph your artwork in diffuse, natural light. Cloudy days are the best for this. You can even consider photographing your work outside, if at all possible.
If you have professional lighting equipment, i.e. lights with photo umbrellas or soft-boxes, place them at a 45 degree angle from your work when photographing. This way, any glare does not bounce directly back into your camera.
Squaring your artwork
Look through the viewfinder, or at the screen, and make sure the edges of your artwork are parallel to the edges of the photograph. This is a very important step for those photographing rectangular 2D works.
If you realize after the fact that your photo is not properly squared, and for some reason you can't go back and take more, you can use a tool in Adobe Photoshop called "Perspective Warp". Search for it in the search bar, and it should come up. Move the corners of the box to line up with the corners of your artwork, press enter, and you can now adjust the perspective of the photo to make the edges square. If you do not have Photoshop, you can just crop your work to the edges, but you will lose some of your composition in this process. We recommend you do your best to get the original photo as square as possible.
Tips for 3D artworks
For 3D artworks, take a few pictures at different angles to decide which is the best. Though we only accept one photograph per artwork in our competitions, this will not always be the case, and it's good to have a record of your object from multiple viewpoints.
Make sure your object is in the center of the photo, and that the background is neutral and without distractions.
Using a Tripod
Ideally, you will use a tripod and manual settings on a DSLR camera to photograph your artwork. Of course, this is not always possible. But you can make a makeshift tripod with a stack of books, cardboard boxes, or whatever else you can find. Even if you're using an iPhone, this will help the image to be clearer. Using a self-timer will help avoid any shake as well.
If you do happen to have a DSLR to use, the ideal settings for crisp, bright images are as follows: ISO 100, f-stop 8-11. Definitely use a tripod and a self-timer if you plan on photographing using manual settings. You might also want to shoot your photos in Camera RAW -- but only do so if you have access to an image processing tool like Adobe Photoshop. We only accept JPEG files in all our competitions.
Scanning your artwork
If you have access to a scanner bed and your work can fit in it, this is a great and easy way to document your 2D work. Just make sure the scanner is set to scan photos or artwork in color.
Editing your photographs
Adobe Photoshop is a great tool for editing your photographs, and a worthy investment if you plan on pursuing art professionally. But there are plenty of free or cheap programs you can use for minor corrections, including Gimp, and this is an important step in the process. Take this time to make sure your images are evenly cropped, properly exposed, and color corrected (i.e., the whites actually look white, not yellow or blue.)
Additional information and helpful links
Four steps to photographing your work like a professional
How to photograph a painting, step by step
The Zero-Budget Guide to Photographing Artwork
YouTube Tutorial: Photographing art with an iPhone
Youtube Tutorial: Photographing art with a Point-and-Shoot