11. Don’t say: [in the middle of a project] “By the way, I’ll need these other related items in addition to the initial design. Can you do that?”

Why? Expanding the scope of your design project in the middle of that project, after agreeing upon a certain arrangement (e.g., you’ve agreed on a logo package, and now you’re asking for business cards and a letterhead design in addition), is one of the worst things you can do from a designer’s perspective — especially if you expect those additions to be included in the original price. This is where a creative brief comes in handy (again). Including the full scope of the project within the brief ensures that you and your designer are on the same page and can plan your budget and timeline accordingly, preventing unnecessary frustration. If you do run into extra, unexpected needs during the course of the project, you’ll need to work out a new budget and timeline for those additions.