Game links.
Unfinished explanations.
Information left out because it's "obvious".
This can cause miscommunication and problems, I need a clear explanation on what to create.
A design brief is something for a developer to refer to when creating a clients idea. For this to work it must be extremely descriptive. These are the main problems developers experience when trying to complete commissions:
Incomplete Descriptions
You know what you want, but to others it may not make sense. Consider on whether you've left out a massive feature which seems "obvious" to you.
Changing / Conflicting Descriptions
Rather than considering the finished product and how it will look, consider the things inbetween. Don't just say "staff only", tell the developer how the system should differentiate staff from none-staff.
Images / References
Exact descriptions of each feature.
Small paragraphs per feature.
Irrelevant information, storylines.
Large grouped text.