I read in bed, and on the balcony when at home. I am lost without reading material if I am on a long bus ride, or waiting for an appointment.
I don't prime myself for a long reading session because I don't care how long I read. When I am tired of reading or life intrudes I just stop. Could be after 10 minute or after 2 hours.
The key to increasing your reading is (my opinion only) to read things you like to read and to have them handy. If you want to read in the bathroom, you must have something to read in the bathroom as you are unlikely to get up and stroll around looking for a book.
Same in bed and on the bus
Habit building is perhaps as important. I am in the habit of reading to take my mind of things before I go to sleep. I am in the habit of reading to take my mind of the tedium of waiting in the doctor's office etc. I have had the habit of reading as entertainment since I was 3 and the other habits probably were built on that, but for those that haven't read a lot, I think reading a bit here and a bit there and always having a book you enjoy ready for when the opportunity or the mood strikes is a good approach. The main thing is to actually enjoy what you are reading.
Helen