Reading for any subject
Be selective. You are not expected to read books from cover to cover.
Change strategy. You need to develop skills in changing from one kind of reading to another, depending on how useful the information is for your purposes.
Use the index pages at the end of a book. Find the exact pages for what you need.
Read from paper. Avoid reading for long periods from computer screens if using the internet: print out an electronic copy in a font that suits you.
Set targets. It is easy to lose focus when reading. Set yourself targets to complete a reading task, with clear objectives for what you want to achieve.
Focus. Jot down a list of questions before you read and as you go along. This will improve your attention - and save you from getting side-tracked.