The rake is another useful technique which is used in Blues playing. It involves fretting a note and laying a finger (or fingers) across two or three adjacent strings. The pick is then raked across the strings, causing a muted sound leading up to the original note which is left ringing. A rake is indicated by an arrow in the tablature pointing up to the note to be raked.
Here is a lick which makes use of the rake.
Another thing you may encounter in slow Blues songs is thirty second notes. One sixteenth note divides into two thirty second notes. The following example is shown in ) time, which is equivalent to half a bar of + time. The thirty second notes are counted 1e+a 2e+a 3e+a, 2e+a 2e+a 3e+a, etc, but are probably best felt rather than counted.