6 - Be Consistent In Your Choice Of Colors. 

I wanted teal blue on my business name cards. I couldn't open the .ai files the designer sent me at the end of my contest, and when I got my professional business namecard printed, they were green. 

The colors look different depending on the screen you are viewing them on. So take the time to consult a standardized color chart before finalizing the design. 

7 - Let Yourself Be Surprised. 

Don't put too many constraints on graphic designers, even if you think you already know what you want. They are talented and may very well surprise you pleasantly if you let them!