Sketching Mars is relatively easy. Many observers use standard-size blank forms— for example, 2 inches (50 mm) to the Martian diameter— but these are too large for times when the Martian disk is small. They will tempt you to put down details you cannot really see.
A better course is to use an image scale of 2 mm per arcsecond. Circles work well for much of the time, but three to four months before and after opposition, Mars's disk looks distinctly gibbous—much like the Moon three or four days before Full—and you should modify your sketch blank to reflect this shape.
Photographing Mars, on the other hand, is a lot more difficult. The small planet demands a long focal length, and this means you need exposures of several seconds. "Windows" of good seeing seldom last this long, so capturing a sharp image on film depends mostly on luck. Many Mars photographers now use CCD cameras. These are just as subject to seeing requirements, but they let you quickly take many short exposures, at least some of which will catch Mars during moments of crisp seeing.