The single stroke roll is the most common drum rudiment used on the drum set. It's often played in beats, fills, and drum solos. It doesn't matter if you are new to the drums, or if you have been playing for years, the single stroke roll is absolutely essential.
It's played with simple alternating single strokes (R, L, R, L). It is best to start practicing this on a practice pad, and then eventually take it to the kit. Once you can play it in perfect time with a metronome, begin to speed up the tempo to increase your overall speed and endurance.
Focus on keeping all the strokes at an even volume. Watch how your sticks come up for each stroke, and be sure they reach an even height. If one stick is coming up higher than the other, it will typically create a louder stroke. Practicing in front of a mirror is highly recommended, so you can keep an eye on both hands while first developing this rudiment.