During that time, I picked up some useful advice from art directors looking at my portfolio. Here are some tips if you are interested to work in illustration:
Do mock ups! Inspire the people you want to work with and show them how your work looks in context.
Draw more than one character! Make them interact. It will be much easier for a commissioner to book you if they know you can tell the story.
Be style consistent on your portfolio. Experimenting is great but multiple personalities on your portfolio will not bring you more commissions.