The Blues a primer:
Besides all the esoteric talk about ' Call and response','Playing with soul',' Dil se bajao' and all this rubbish please focus on the syntax otherwise you will seriously disturb the 'souls,'hearts', and a lot more of all the listeners who hear you.
The blues is an emotive form and has a vocabulary.There are scale forms that are used from where all the cliches you hear are born. Every rock n roll lick,every small embellishment however kinky is part of a scale or a hybrid mix of more than one scale.
Let us take a simple 12 bar progression which I assume you guys are familiar with. The chords are say G7,C7 and D7. The 1,4 and 5 chords.When you start off on the G7 chord and before you start jumping around trying to reach that one favourite lick take a short while to understand the chord.
On this G7 try the following options: G Mixolydian (the notes of the C major scale),the Minor Pentatonics in the 1,2,5 and 6th degrees(for the 2nd and 5th avoid the 4th's),The melodic minor up a 5th i.e. D melodic minor,The half whole diminished scale starting at G,The whole tone scale starting at G.Some of these options will give you an 'outside sound'.This paragraph is a data intensive block and read this carefully or you will land up playing with your 'soul'.
When you move to the 4 chord i.e. the C7 the main sound you will hear are the notes of the F major starting at C.Try this for now and see how nicely the change from G7 to C7 has been made.
Do not philosophize with names and stuff and ask questions. DO IT and you will hear it I guarantee.There are many more things you can do here but start with this.
On the turn around which is the movement of the 5-4-1,people have played really interesting things and you will too if you understand how the chords resolve back to the 1. Try the mixolydian ideas for the 1 chord over the 5 chord. Try a motif with the chord tones of the 5 chord and resolve it to the 1 chord via the 4 chord.This is a 'creative' part of these changes and you can quote nursery rhymes,the upanishads or anything you feel like as long as you resolve the idea to the 1 chord to which the progression finally comes to rest.Try using small licks from the data given and transpose them to the other keys to make the idea float 'through' the changes.The bottom line is to TRY.
Go through the posts and you will see a few videos on bends and cliched phrases.The newer ones I will record will take you through each chord and give you ideas on how to approach stuff.Please read the posts and make charts on every scale that you will use in order to gain control of the fretboard. This is imperative and needs to be done by you. As one guy said 'this is not fun anymore'.LOL get with it and you will see and enjoy several levels of 'fun',I absolutely assure you :). And hey please,please for god sake work on the vibrato it will make or break your blues career :D.

http://www.youtube.com/watch?v=eIXIVbRa9vw