The most important thing to convey in the photograph is your favourite part of the artwork. Make the image visually appealing and interesting to yourself, as this will translate to your audience.
Remove the background surrounding the artwork. Try cropping your artwork by removing the surrounding areas and shadows to make for a cleaner image.
Reflections are the biggest challenge when photographing artwork. The best way to avoid this is to remove the glass or to roll some tape behind the photograph to change the angle.
The best angle for artwork is straight on if possible. Ensure the image is not blurry. Try using a tripod to assist.
Keep a clean background. Try photographing your work in front of a blank wall or table, without the background clutter.
The best light is indirect, white light. When possible, take the photograph using natural light.