It is important for every musician to build a library of riffs to call upon when involved in musical creation. If you are a keyboardist, you must be able to translate things quickly from your mind to your fingers. The best way to have success with this is to learn as many scales and riffs as possible to provide yourself with the most options for what you want to play. If you have any desire to play a standard rock lead, you must be aware of the basic blues scales and their fingerings.
The following example outlines a C blues scale. The scale is made up of a minor pentatonic scale (C, Eb, F, G, Bb) with the addition of the flatted 5th (Gb or F#) - this flatted 5th is the "magic note" that gives the scale its bluesy sound. Pay very close attention to teh fingering. The C blues scale is one of the more challenging blues scales to play that begins on a white note. I use the fifth finger at the top of the run for ease and convenience.