The Basics
Two point perspective involves the use of two vanishing points, as opposed to one. This can be seen in the photograph below.
Step one - Begin by drawing the two vanishing points, ensuring to keep them running in line with the edge of the page. Sketch the first vertical line which will be the closest line to the viewpoint in the drawing.
Step two - Using much more faint lines, draw from the top of this line two more lines which run back to the two vanishing points. Repeat this for the bottom of the line as well, so you should end up with the shape seen to the left.
Step three - Begin to flesh out the drawing by adding in details such as seen to the left. Ensure that any line which is not vertical, and yet would, if looked at the scene from straight on, be horizontal, runs to the vanishing point, as can be seen from the drawing.
Step four - Add the final details and you're done!