Standing while learning is better still. And walking while learning is best of all, provided you're in familiar territory and don't stumble over anything. And if you are firmly gripping something while in any of these positions, they you increase the level of learning for that position. So the best position would be to walk while gripping your book. Another tip is to study in the place where you will have to recall the material.
Studies show that environmental cues help trigger our memories.
It's so important, whenever possible, to sleep following your study. Unless you are very fatigued, you'll find it best to study at night and review in the morning. Sleep improves retention greatly because the brain has time to consolidate the material without added interference. So if you are studying for a lot of tests, it would be good for you to take a nap several times a day. When you're studying a series of subjects, one right after another, make sure the subjects are dissimilar.