To practice any major scale, you should practice playing it in all five of these positions. Start at the root and play down to the lowest note in the position, and back up. Then, go all the way up to the highest note, and come back down to the root. The tempo of your notes should be as steady as you can make it.
Once you're comfortable with each position, shift between them. Try playing multi-octave scales, or just take a solo. Once you know the patterns for a major scale, you'll have an easy time learning a major pentatonic or minor scale.