We all aspire to be blues and jazz masters at the piano, but there are some easy blues piano tricks that every pianist should know which can instantly give your playing that authentic blues sound. The masters - pianists like Wynton Kelly, Oscar Peterson, Otis Spann, Dr. John, etc. - all knew how to use these easy blues piano tricks to perfection. The things about blues piano tricks is that they sound great when you sprinkle them in occasionally, but shouldn't be the basis for an entire solo. So use them sparingly and listen to lots of blues pianists and recordings so that you can get a sense of how and when they're played effectively.
What a lot of pianists call a "roll" is actually, in academic music-speak, referred to as a tremolo. A tremolo is a very quick repeat of a note or notes which produces a quivering or wavering sound effect. The symbol for a tremolo is a line or lines written horizontally through the stem of the notes which are meant to be rolled. Here's an example of a fairly classic two-handed use of the tremolo effect in a blues format. The right hand is "rolling" the melody notes in octaves while the left hand is "rolling" the rootless chord voicing. When played together, it produces a big, robust sound.
This might not seem like much of a blues piano trick, but being able to play some quick blues scale runs is an absolute-must for blues pianists. There have been some great, maybe even epic blues-rock guitar solos that use only notes from the blues scale (check out some Stevie Ray Vaughan or B.B. King for evidence of this). The same is true for piano players. You can always buy some time in your solo by ripping a blues scale run or two. So make sure you're able to play up and down the blues scale at a moderate to fast tempo.
This is a blues lick that gets played ALL the time. Every blues piano player should know it because although it is played quite regularly it sounds awesome, not tired or overplayed. It's takes a little bit of practice to get under the fingers but not something that is difficult. It works great in the blues form, but especially great if you start it in measure 9 where the ii-V-I sequence begins.
This is another very common bluesy piano sound. Again you'll be rolling (or playing a tremolo) across two notes in the right hand - the 5th and 7th of the chord. For example, if the chord is an F7 chord you would tremolo the 'C' and 'Eb.' If the chord is Bb7 you would tremolo the 'F' and 'Ab.'
A great place to start experimenting with some "outside" playing is in measure 4 of the 12-bar blues form. Normally we would play the 'I' chord in measure 4, but by playing a tritone substitution in that measure you can get some advanced "outside" sounds. In our example in the key of F, we would play a B7 chord in measure 4. Experiment with comping and soloing in this measure using the tritone substitution.