1. Need to be Able to Read it
This is pretty self-explanatory. If nobody can read your logo or know what the name of your company is, how can they talk about you with their friends? How can they look you up in the phone book or get any kind of information on you for that matter?
2. Needs to be Memorable
If a customer sees your logo only a few times and remembers the meaning of it, then you know you have a winner.
3. Needs to Reflect the Interests of Your Target Market
Can you imagine Harley Davidson's logo having cute little cartoon bears and colorful unicorns bedazzled all over it? If you're thinking that would be awkward, then I'm right there with ya. Your logo needs to reflect the interests of your target market.