Tutorial : How to Draw Graffiti Bubble Letters ?

In the art of graffiti there are many types of design in their construction. Call it like wildstyle, MindGem, Throwup, flava, bubble and many more. But the most easily made and studied by a beginner is graffiti bubble effects model. That's because in the making we just made a circle, not a round circle but an oval circle appropriate design will be made. Then how to make graffiti bubble letters?