Use of Lines to Sketch

When sketching out your painting onto your surface of choice, it is a good idea to sketch using straight lines only- curves lines make sketching too difficult. It's easier for the brain to comprehend straight lines than it is to understand curves.

You can break down curves into multiple straight lines for the most part. You need to capture your images big shapes and overall outlines. When sketching you should be constantly be comparing how each line relates to others in the composition. You need to see how each of the lines intersect or would intersect with each other if the line continued on in each direction.

You should look at you subject as a series of shapes not as name-able parts of an object. Look for angles, shapes such as squares, triangles, rectangles, etc.