Ryron Gracie shares a drill he likes to use that can help you when you need to move from side to side for an arm lock. Sometimes the armlock on the same side can be tough to finish with a really strong guy who sees it coming and grips up.
If you can smoothly flow to the other side you'll have another chance to attack, but the movement can be difficult to master. Give this drill a try and let us know what you think!