Before you can write your portfolio essay, you must select the pieces you want to include inside of your portfolio. Without knowing what’s going to be inside of your portfolio, it’s difficult to write the essay. In some cases, your teacher or professor will tell you what pieces needed to be included in your portfolio. If it’s an online writing portfolio, you’ll need to upload the documents instead of putting them into a binder. Whatever format your portfolio will be in, there’s also a chance that your teacher may not give you guidelines at all and will merely give you suggestions. If this is the case, then try to showcase your work through as many mediums as possible. Portfolios are best when there is a bit of a variety.