Tips on sketchbook? (Illustration)

[FirstCircle]

I'm applying for OCADU for illustration, and I need help on my sketchbook. I recently went to the National Portfolio day at OCADU, and the person who was criticizing me told me that my sketchbook was lacking a lot of things. He told me that my sketchbook does not have enough things to show progress. I showed him that I had thumbnails, but he said that was not enough. There needed to be more. I can't really think of any other ways to show 'progress'. Any ideas?
Also, any tips on sketchbooks would be nice. So far I have some still life, and my own ideas. Anything else?

[heavenwill]

Showing your sketchbook here could help

[themegagod]

1. show your sketchbook

2. draw from observation

3. Draw a lot.

If you don't show your sketchbook on here, how is anyone supposed to tell you what's wrong with it?