I know I don’t have the best solution, but here are a few things I do.
1. I try to keep the list as short as possible. Dealing with long lists is painful. I skim through a lot of things and only about 10% of those make my to-read list. Initially, skimming may take a lot of time. However, once you are accustomed, you know what and where to look for. I usually don’t add articles, blogs, research papers, etc. to the list. I read them immediately or on the same day. Books and really long articles are the ones that go on the list.
2. I review the list once a month (I try to do it on the first day of the month; it helps me remember to do it). This is when I prioritize. Rarely, I even discard something that I don’t need to go through in the near future.
3. I rely more on the digital content since reorganizing, highlighting, and discarding is easier. Sometimes, a PDF manager or a citation manager helps. Mendeley has the option of marking an article/ book/ anything actually as read or unread. You can also create folders in Mendeley to prioritize your stuff.