Here are some rhythmic figures which combine sixteenth notes and eighth notes within one beat. These figures are very common in many styles, so you will need to know them well. Practice each one carefully and be sure to tap your foot and count.
Once you have learned these rhythms on a single note, try using them with the minor pentatonic scale as shown here. The more familiar you are with these rhythms, the easier you will find it to play melodies containing 16th notes, as well as improvising with them.
This 12 Bar Blues is a classic R&B riff making use of both eighth notes and sixteenth notes. The chords used here are the C7 shape played as a G7 (8th fret) along with root 6 C7 and D7 bar chords.