1.) Choose a photograph. We're using Illinois, local, spring and summer related flora and fauna.
2.) Use a laminate plasticine paper to sketch the grid.
3.) Draw a grid, larger than the photograph onto a separate sheet of paper.
4.) Refer to the grid laminate and photograph to draw value and/or color onto the larger sheet of paper.
Simple. The psychology of it all? Basically, the grid blocks out sections so that you can maintain proportions, and focus on individual sections.