I need a logo design for my business, what should I include in the brief for the designer?
When creating a logo design brief for a designer, it is important to provide clear and detailed information about your business, target audience, and desired design elements. Here are some key elements to include in your brief:

1 - Business name and description: Make sure to provide the business name and a brief description of the products or services offered.
2 - Target audience: Who is the target audience for your business? What are their age, gender, interests, etc?
3 - Design style preferences: Do you have any specific design styles in mind, such as minimalist, modern, or playful?
4 - Colors: What colors do you want to include in the design? Do you have any specific color preferences or brand colors that need to be used?
5 - Image and icon usage: Do you want the design to include images, icons, or symbols that are relevant to your business?
6 - Brand values: What values or messages do you want the design to communicate about your business?
7 - Competitor research: Have you done any research into your competitors' logos? What do you like or dislike about their designs?
8 - Format requirements: What format do you need the final logo design to be delivered in? Do you need it in vector format, for example?
What is a common mistake that can be made when creating a logo?
A common mistake when creating a logo is not relating the logo to your brand. Whether it's the colors, the symbolism, or even how complex the logo is, if it doesn't relate to your business and what you do, it won't turn out well. For colors, try to use colors that relate to your brand, such as the blue and yellow IKEA logo, and avoid colors that aren't related to your brand. In the case of symbols and overall design, make sure any symbols and shapes in your logo relate to your brand. Good examples of this are the Apple logo being a stylized apple or the McDonald's logo being a capital M. 

If you need more help with designing your logo, please ask more questions or do your own research on logo design related websites.