I've already read a couple of books, but they were all light reading or straight to the point. Today I started volume 1 of Capital. I read for about 2 hours and I realized I feel like I can't do this; it's very dense and abstract. Are there any habits, thoughts, or other helpful things that keep you focused?
Lots of great advice in thread already. One thing I would say is don't feel the pressure to understand everything the first time you read it. For texts you want to go deep into I would suggest reading it three times.
First time you just read/skim it, try to read it uninterrupted and don't get hung up on details or footnotes. Second time, you do annotations and write questions about the text in the margins. Third time you read the text to answer your questions.
This short article on how to read philosophy also gives good pointers. https://philosophy.arizona.edu/sites/philosophy.arizona.edu/files/Rosati%2C%20How%20to%20Read%20a%20Philosophical%20Article%20or%20Book.pdf