Apart from books, your most important source of information will be recordings. Listen to the guitarist on any Blues album and you will hear note bending, slides, grace notes and all the other techniques which make Blues guitar such a great sound.
Some guitarists to look out for are BB King, Otis Rush, Buddy Guy (with Junior Wells or solo), Magic Sam, Lightnin’ Hopkins, T-Bone Walker, Albert King, Freddy King, Debbie Davies, Peter Green, Hollywood Fats, Gatemouth Brown, Albert Collins, Jimmie Vaughan and Stevie Ray Vaughan.
There are also numerous great Jazz and Blues sax players who are worth checking out. T Bone Walker and BB King got a lot of their original ideas from listening to sax players. Some of the most Bluesy sax players are: Maceo Parker and Pee Wee Ellis (Solo or with James Brown) King Curtis, Junior Walker, Fathead Newman, A.C. Reed, Eddie Shaw, Eddie “Cleanhead” Vinson, Scott Page, Illinois Jacquet, Stanley Turrentine, Eddie Harris, Ben Webster, Johnny Hodges, and Roland Kirk who often played two saxophones at a time!
When you are listening to albums, try to sing along with the solos and visualize which strings and frets you would play and the techniques you would use to achieve the sounds you are hearing. This helps you absorb the music and before long, it starts to come out in your own playing. It is also valuable to play along with albums, sometimes imitating what you are hearing and other times improvising. This is very good ear training and is also a lot of fun.