Grid Art

The grid method is an inexpensive, low-tech way to reproduce and/or enlarge an image that you want to paint or draw. The grid method can be a fairly time-intensive process, depending on how large and detailed your painting will be. While the process is not as quick as using a projector or transfer paper, it does have the added benefit of helping to improve your drawing and observational skills.
In a nutshell, the grid method involves drawing a grid over your reference photo, and then drawing a grid of equal ratio on your work surface (paper, canvas, wood panel, etc). Then you draw the image on your canvas, focusing on one square at a time, until the entire image has been transferred. Once you're finished, you simply erase or paint over the grid lines, and start working on your painting, which will be now be in perfect proportion! Yay.
To use the grid method, you need to have a ruler, a paper copy of your reference image, and a pencil to draw lines on the image. You will also need a work surface upon which you will be transferring the photo, such as paper, canvas, wood panel, etc.
To draw the grid lines on paper, I would recommend using a mechanical pencil, so that you can get a thin, precise line. Be sure to draw the grid very lightly, so that you can easily erase it when you are finished.
To draw the grid lines on canvas or wood, I would suggest using a thin piece of sharpened charcoal. Again, make sure you make the grid lines as light as possible, so that they are easy to erase when you are finished. The benefit of using charcoal on canvas or wood, instead of using pencil, is that charcoal can be easily wiped off with a paper towel or rag, whereas pencil can be more difficult to erase.
The important thing to remember when drawing the grids is that they must have a 1:1 ratio. This is very important - otherwise your drawing will be distorted! Basically, a 1:1 ratio means that you will have the exact same number of lines on your canvas as you will on your reference photo, and that in both cases, the lines must be equally spaced apart - perfect squares.
Confused? It's quite easy once you get the hang of it. Let's see the grid method in action, and it will make more sense.