If you’re not already drawing but are interested (which I guess you are as you’re reading this) then really the number one rule must be to draw regularly.
In my opinion just making marks in a pocket sketchbook on a near-daily basis is more important than intently studying how to draw for hours but not actually drawing. If you want to draw – draw!!
These two were done on holiday. Both relatively rough and ready sketches but bring back more memories of the experience than a photo ever would.