When going for an Americana:
I'm assuming you already know how to do an Americana. If you don't, look it up on www.lockflow.com
Let's assume you're going for his left arm. With the figure four locked in, "motorcycle" his left wrist out before pulling his elbow in to his body. In other words, you're holding his left wrist with your left hand. Roll his left wrist outward like you're accelerating on a motorcycle. Then pull his elbow in to his side.
For a lot of people, you won't even have to lift their elbow to get the submission. As soon as you motorcycle their wrist out and pull their elbow in toward their body they'll tap.
This is especially useful when someone has flexible shoulders. You may have to lift their elbow at the end, but you won't have to lift it very far!