Jenna Moreci's video is not only entertaining (with some NSFW language) but it's chock full of some great tips for both the writer and the beta reader. Here are some tips for you if you decide to ask me to beta for you.
I'm in the middle of a a great beta read. The novel is in a genre that is fun, and the text is well-edited overall. While beta reading is often this way, there are some things that you should consider, especially if you want to ask me (or really anyone) to be your beta reader: