MarketingProfs.com have put out a two-part series about logos and they are great. If you’re considering a logo or working with one, these are a must-read. A summary of Logos: What Makes Them Work Part 1 and Part 2:

Developing a great logo is a strange mix of art, science, psychology and (in most cases) a good amount of luck.

…First, let’s make one thing very clear. You logo is not your brand. Your logo only represents your brand…Your logo is nothing more (and certainly, nothing less) than a visual mark that represents your brand.

They then go into the points of how to create one:

• Good logos are designed in black and white first. Color comes later…
• Logos are first recognized by shape, then by color…
• Just like the shape of a logo, color needs to be simple and easy to recognize and memorize…

Part 2 continues:

• If you saw a logo with a hamburger in it, you’d think the place sells hamburgers. When you see the Golden Arches, you think of McDonalds, not Burger King…Logos, over time, come to represent the company. They don’t have to be literal translations of what the business does.
• Strange as it seems, some logos fail because they were never checked for size…You want to be sure that the logo works well on business cards, letterhead and envelopes…
• Don’t be tempted to tear the design apart looking for hidden meaning or to be an art critic. That kind of stuff is best left to the goofballs who hang out at galleries pretending to enjoy those little triangular sandwiches as they make totally irrational interpretations of what they see…look at the logo proposals the same way that the public will look at your logo—quickly…