Dan Heath and Chip Heath provide evidence in this Fast Company article that the interview process may not find the most qualified people for your company.
Instead, the past performance of a person is the best indicator of future performance. Asking a person to perform a job test and demonstrate his skills helps discover the true stars.
As a person interviewing for a job, you can't count on the company to always give you the opportunity to demonstrate your skills. So I suggest you do what many graphic artists do — Start to build a portfolio of your accomplishments. Lead the high-profile projects in your company and then create a visual of your success. This could be a graph of the costs you cut for the next 12 months or the revenue you generated over the next year. You could also draw a Venn diagram to show how the intersection of your skills creates a distinct advantage for your new employer.
And when you're in the interview, go into demo mode at your first opportunity. Treat the interview as a consulting opportunity and show the hiring company how new technologies or a new marketing plan will drive customers to its doorstep.