I draw out the divs on a piece of paper, helps me map the site from the PSD.
Then start splicing if you NEED images, most can be done in CSS nowadays. Then get the old marque tool and get the sizes of the divs you mapped out and code away.
BTW, many developers, not all, are moving away from a fixed-width layout and going for responsive design so the layout fits a wider range of screens, including desktop, tablet, and mobile phones.
Otherwise, you might try sketching it out on paper first, using a grid, and put dimensions in pixels in the containers.