A Pentatonic scale will always have five notes. Pentatonic has been derived from the Greek word pente meaning Five and Tonic meaning Tones or Notes. A Pentatonic scales is formed by taking 5 notes from an Octave or 7 Notes in a Major or Minor scale or any diatonic scale.  If you learn Major and Minor pentatonic scales that is more than 90% of your job is over on Pentatonic scales.

Pentatonic scale is widely used around the world. It is used in American, Latin, Asian and various other types of music around the world.

Pentatonic scales are the life blood of Rock Guitarists in particular and Rock music in general. It is used in Blues, Jazz, Bluesgrass, Metal and mostly every form of western music that you can name.

There are many varieties of Pentatonic scales, but we will only look at Major and Minor Pentatonic scales, because that's more than enough.

To play some melodic Pentatonic scale solos, you need to practice the scales daily for 2-3 hours in different styles. First start out slow and then gradually increase your speed.

A Major Pentatonic scale can be derived from any diatonic major scale.

Here I am going to take the example of C Major scale for which, the notes are C D E F G A B C

A Pentatonic scale is formed by taking the 1st - 2nd -3rd - 5th and 6th notes from a Major Scale.So the notes of a C Major Pentatonic scale would be C D E G A.Now, try practicing these notes in different positions(Fret Positions) on your guitar and also in different styles, using Bending, Tapping, Hammer ons and stuff like that.

You can also build a Major Pentatonic scale by applying this formula below on a Chromatic scale

Whole - Whole - Whole & Half - Whole - Whole & Half (where Whole is Whole Step or Full Tone and Half denotes Half Step or Semitone)

How to build a Minor Pentatonic scale ?

If you are more inclined to Bluesy kind of music, then this is the scale for you. You can play excellent bluesy sounding riffs using this scale.

A Pentatonic Minor scale is formed by taking the 1st - Flat 3rd - 4th-5th and Flat 7th notes from a Major Scale.So C Minor Pentatonic notes would be C E Flat F G B Flat

A Minor pentatonic scale also can be formed by applying the below formula on a Chromatic scale:

Whole & Half - Whole - Whole - Whole & Half - Whole

For getting ideas on different styles of playing keep listening to different styles of playing by different guitarists.

And the key to becoming a perfect guitarist is by learning different styles and practicing it hard.