There is no best way to prepare a figure for insertion into a document, for example in a homework prepared with TeXwins. There are two things to consider:
What is the minimum acceptible quality?
How much effort can I afford in the "learning curve"?
For the current course, we have developed an option that produces adequate images and has a relatively shallow learning curve. It requires KSEG and a simple "paint" program. On Windows, use the utility Paint that comes with your system. On a Mac, 10.5 obtain the free iPaint clone of Microsoft Paint.
Draw a right triangle $ \triangle Y X^\sigma X $.
Find the midpoint $ A $ of the hypotenuse $ Y X $ and midpoint $ X_\ell $ of the vertical side $ X X^\sigma $.
Draw and label as $ \ell $ the line through these midpoints.
Sign the picture with a date and your initials.
KSEG can do the drawing itself quickly and efficiently. Even without the curly "ell" and the Greek sigma, KSEG is clumsy at relabelling points, and inserting text in general. So we shall use Paint to do that part. So draw the figure about 2 inches wide and 1.5 inches tall. Then export it as a bitmap file (.png, for example)
In Paint, type in the letters the clear. You’ll need 3 X’s, two of which are decorated with symbols NOT available in Paint. But you can use the paintbrush to draw a reasonable picture of the ell and the sigma.
Here is a video of a simpler example than the above.