I just tried using two of your tips on the weekend. The pinhead stitch is wonderful especially since I am doing a rather large chart - Lady with Unicorn - Sense of Taste. This has many colour changes and this stitch really helps. Also marking off all one colour in yellow highlighter then a darker colour on top really speeds things up and it is much easier on the eyes, not searching for the next symbol of the colour.
Coalbrookdale by Night Philip James de Loutherbourg