The major pentatonic scale is made from these note intervals: root note-2-3-5-6. In the key of C that is C-D-E-G-A. This scale stays the same no matter what key you are in. You should memorize the intervals of the major pentatonic scale.
Start in the key of C and begin to play the scale. Begin at a slow tempo and don't worry about mistakes. Just practice playing the scale--C-D-E-G-A--once, then begin again.
Once you can play the scale easily, practice playing it backwards. After you play C-D-E-G-A, do not stop--instead, play A-G-E-D-C immediately after. Doing this will allow you to truly understand the way the scale sounds and help with your playing dexterity.
A minor pentatonic scale is made from these note intervals: root note-3b-4-5-7b. In the key of C, that is C-Eb-F-G-Bb. As with the major pentatonic scale, this progression always stays the same no matter what the key is. Memorize these intervals as well.
Start in the key of C and play the scale slowly. Play C-Eb-F-G-Bb, and then stop. Do this until it feels comfortable, and you can play the scale without stopping to find the next note.
Once you can play the minor scale easily, learn to play it backwards. Play C-Eb-F-G-Bb, and then play Bb-G-F-Eb-C immediately after.
Practice these basic intervals in a variety of keys and and neck positions. Try to practice this at least 20 minutes every time. Don't get discouraged if you can't play the scales up and down the neck at blazing speed. That takes time, and as long as you are practicing, you will master the pentatonic scales.