1. Beginning the design process without an explicit objective.
Take the time upfront to meet with your client. Ask them questions about their business, who are the major competitors, what are the goals of this company, who is their audience, etc. Filling out a creative brief with your client is a good habit to get into for starting new projects.
2. Designing in a vacuum.
Not knowing what your clients competition is doing can be detrimental. Take the time to talk with your client about the competition, then do some further research on your own. It will help you to arrive a stronger solution in the end.
3. Not being able to answer the question “Why?”
Not having a solid strategy or rationale behind your design that ties in with the clients business objectives can make it hard to defend and sell the logo to your client. Personal tastes are easily introduced when all the designer has to say is, “This logo is cool.” If you can’t answer why, it’s also highly likely, you as the designer haven’t adequately considered your clients needs and business strategy.
4. Going to the computer too early in the design process.
Start your concepts with paper and pencil. Going to the computer to early can limit your creativity. It is much easier to work loose and quickly on paper.
5. Not listening to feedback from someone because of who they are.
All feedback is valuable. Swallow your ego, and listen, you never know what insight you might find.
6. Not choosing the right typography.
Choosing a typeface is an important part of the logo design process. Helvetica and Times are not the only options and in most cases are not the appropriate option either. Take the time to find the right one and then refine and tweak it as necessary.
7. Not considering the applications the logo will need to be used in.
It’s easy to create a detailed logo that doesn’t reproduce well in all applications. Understand your clients needs and limitations when design the logo.
8. Using computer/application tricks.
The computer is a great tool, but it will not make your bad logo good. Adding effects, like bevels or shadows, etc., to dress up a bad logo will not make it better.
9. Showing too many options to the client.
Narrow down your concepts for the first client review to about 3-5 concepts, which is adequate in most cases. Use your skills as a designer to pick the most appropriate designs. By doing this you eliminate the crap and will also streamline the whole process.
10. Presenting a design you don’t want the client to choose.
If you have a design you don’t want the client to choose, Just don't show it! All too many times the client chooses the one we don’t want them to. Why give them the option?