would love some insight

I have an unrelated-to-ID Bachelor’s degree already, and I would like to go for a Master’s degree in ID. That means that I have to put together a portfolio - this has been very difficult for me because I have to create things in order to put them into the portfolio, rather than decide on past projects and rework them. If anyone has any advice or experience with this, I was hoping for your insight. I have so many questions, like, how many pieces should I strive to put into my portfolio? How should each project be represented, i.e. sketches, final drawings and then renderings?

Thank you in advance, I’m kind of crippled by the anxiety.