1)Read with a purpose.
2)Skim first.
3)Get the reading mechanics right.
4)Be judicious in highlighting and note taking.
5)Think in pictures.
6)Rehearse as you go along.
7)Stay within your attention span and work to increase that span
Just reading is not enough , retention is must and for that you must enjoy reading because when you do something with full interest and enjoy doing so,you tend to retain those moments and same is with books.The more you read,the more you learn,the more youu enjoy , the more you retain.