Since these major scale forms do not always start and end on the root, here is a good way to practice them. Start on the lowest root within the form. Then go down to the lowest note in the scale form, and return back up to the lowest root. You may even want to pause slightly on the root, just so that your ear can relate all of the other notes in the scale to that root. Then work your way to the highest note in the scale form, and then back down to the lowest root again.