Things to think about when you're designing a logo:
2. Contrast. You want a logo with good contrast to improve visibility and to make it able to be seen from a distance. Colors or elements that are muddy or bleed into each other will be harder to see. Be especially careful when layering elements on top of one another.
3. Appropriateness/ sophistication of the drawing and the font. The style and level of sophistication of the art and font choice for your logo will both affect the overall message of your logo. Make sure that everything is drawn and chosen in such a way to reinforce your message instead of detracting from it.
4. Number of colors. If you're planning to print all of your marketing materials digitally, this isn't such a big deal. But if you might be printing things on press, you don't want to have a logo that needs to be printed in full color. It will drive up your printing costs.
5. Black and white translation. If you're planning to run ads or print promotional materials, it's helpful to be able to translate your logo to black and white or greyscale without losing visual impact. Or, even if you're not, it's good to have a black and white option in case you need it in the future.
6. Scalability. You want to be able to scale your logo down to the size of a postage stamp, and up to the size of a sign or truck, without the elements looking too spread out or becoming illegible.
7. Simplicity. Simplicity in a logo contributes to it's memorability – if there are fewer visual elements, the viewer is more likely to absorb them all and remember the logo (or at least recognize it when they see you again).
8. Visual strikingness. You want a logo to have visual presence. You can do this through strong, clear lines in the artwork, an interesting logo layout, an unusual font, or even just by designing it particularly well.
9. Originality. Make sure your logo looks unique. For example, "seal" type logos (logos on a round background, often with words in an arc) are very common in the food industry – which is good because they suggest that the logo is for a company about food, but bad because there are so many seal logos out there for food companies. Don't get lost in the crowd.
10. Don't use an actual photo in your logo. Your logo should be made up entirely of vector art, so that down the line, as you need to use it in different applications, and at different sizes, the quality doesn't suffer and file sizes don't get unmanageable. You can use a photo as a part of your brand and put it on your marketing materials with your logo, but the logo itself should really be vector art.