The guitar takes you on a journey
The 7 Major Scale Patterns form the basic building blocks of guitar. These are arranged as 3 notes per string. Take note of the fingering. Where there is a big stretch I like to widen the the stretch of the 2nd finger. This is stronger than trying to strecth the space between the 3rd and 4th fingers.
Practice the 7 major scale patterns beginning with the natural scale (key of C). The natural scale has no sharps or flats. On a piano this looks like all of the white keys. On the guitar you'll start with the number 4 scale pattern and work your way up the neck with the remaining scale patterns; 5, 6, 7, 1, 2, and 3.
3 TIMES DONE: All items and exercises should be practiced, when reviewed, 3 times in a row without a mistake. This method evens out ones knowledge on the guitar. This eliminates the "dark areas" of the guitar. A student may not need to practice one item as much as another. For example the student may be more or less familiar with scale pattern number 5 but numbers 2 and 3 are just weird. He practiced scale pattern number 5 12 times before he played them 3 times in a row without a mistake. Scale pattern number 2 he practiced 63 times and pattern number 3 78 times before they were "3 times done". In this way one practices what one needs to. After a while his knowledge is uniform across the guitar neck. The guitarist feels comfortable with all patterns anywhere on the neck of the guitar which aids greatly in improvisation when one has no time to think.
1) Practice and memorize all 7 scale patterns.
2) Do them "three times done" in all 12 keys. Go through the circle of fifths when going to a new key; through the flat keys. In other words, you go up an interval of a fourth or down a fifth:
C - F - Bb - Eb - Ab - Db - Gb/F# - B - E - A - D - G - C
Keep in mind the system here: You must pay attention to and KNOW the roots for all of the scale patterns. This will make finding new keys easier.