Grid design basics
Dev.Opera gibt in dem Posting Grid design basics: Grids for Web page layouts einige Tips für Layout Grids.
For grid design, a 960-pixel total width is a good starting point, because it provides a massive amount of scope for divisions (960 is divisible by 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 60, 64, 80, 96, 120, 160, 192, 240, 320 and 480).
That said, too many columns can result in excessive complexity, so when working on initial grid designs, stick to about a dozen columns. The reason for working with 12 columns (rather than, say, seven or ten) is because of the flexibility it affords you in being able to divide the layout evenly (2 x 6, 3 x 4) and also in various other combinations