1. Do NOT adhere to logo design trends. Your designs should be able to stand the test of times.
2. Your logo design should be able to switch mediums - print, web, embroidery, etc.
3. Avoid designing busy logos - remember: the most memorable logos are always the simplest.
4. Don't stick to design software right off the bat - sketch your ideas out first!
5. Take your time when making final touches, it will make all the difference.
6. Never make the mistake of designing a logo in Photoshop. Always use vector or you'll never be able to resize your logo.
7. Never use stock images in a logo design. It's ugly and noticable.
8. Only use readable fonts - don't overuse Helvetica anymore than it already has been though. Too much of a good thing can be a bad thing.
9. Never think a super colorful logo is best. Sometimes it's just gaudy.
10. If your logo design fails in black and white - don't even bother adding color to it. Redesign.
11. Don't be a copy-cat. Be inspired by successful logo design, but never, ever copy.