You need your own elevator pitch. In fact, you're probably working on it right now. It's called "your book."
I can't stress how narrow the window of opportunity is for your book to make an impression on a creative director. I know one award-winning CD who literally flips through student books like he would a magazine. If nothing causes him to stop, he doesn't stop. May not seem fair. But it's how he hires really talented people.
So if your book really is your 30-second elevator pitch, here are a few suggestions for making the most of it:
1. Don't introduce each campaign with a set-up page explaining the strategy. It bogs things down. I've never seen an ad in any medium that was preceded by a paragraph explaining the strategy and target market. Most agency people are smart enough to figure out a strategy from the work itself. (At least the ones you want to work for.)
2. Keep the pages as clean as possible. Just show the ads. If it's an ambient piece, or some other execution that warrants explanation, keep it to no more than a couple lines.
3. It's nice if you want to credit your AD or CW. But don't do it on every page or with every campaign. (See #2.) If you are really so full of appreciation, give a collective shout-out at the end of your book. (Although even that isn't necessary.)
4. Don't try to be cute or clever with your book. I'm not a fan of cute themes because I've seen so very few of them work. I've seen some great ones. But I've seen a mountain of them come off as mediocre arts and crafts projects.
5. Ditto for resumes. I know very few creative directors who are fans of clever resumes. Keep it simple. Save your thinking for your ads.