Your portfolio is undoubtedly one of the most important documents that you will ever put together. It is just as important for your portfolio to showcase your creativity as it is to demonstrate your professionalism, because these are the two essential qualities that any artist/designer/performer should possess. However, too often people will put more focus or attention in one and not the other, and this is just one of the common mistakes that people just starting out will make. Although we should all try to learn from our mistakes, it is important to avoid as many as we can, because it may take a long time before you get another opportunity that's just right for you.
One thing I do really push for, in any sort of portfolio presentation, is the messy stuff. I want to see the designer's PROCESS more than anything else. The notes in the original script, the notes from the production meetings, etc.
From Entertainment Design
“Who am I anyway? Am I my resume?” so goes the lyric from the opening number of A Chorus Line sung by an aspiring triple-threat. For aspiring theatre designers, the answer to the lyric is yes…and no. Design faculty at top colleges can easily see through the gloss of a slick portfolio. An attractive presentation is nice, but if the talent and the ability are not there, the presentation is moot.