Pixels for images that are pixels wide/high, float:left or float:right to wrap them in the page text
ems or %age for fonts, ::do not set any absolute size for screen fonts, the user may have settings you don't know and your page is illegible, lost customer
%age for all other elements
Set separate styles for @media screen and @media print at minimum, on paper set point sizes for fonts.
pages adjust to screen resolution, window size, users display settings,
layout works in multiple browsers and multiple OS
don't attempt to make the page layout exactly anything, too many browsers render differently
just make it work.
this page gets horizontal scroll bars when the window size is small enough,
but, its looks similar, and it works.
- Use percent to arrange objects across the width of the page, and to set the sizes of box objects.
A good plan, but in the case of a fixed width layout, percentages obviously won't work :P I use em if I want a fixed width layout, because em is dependent on text size. Resizing the text in your browser causes the width of the site to stretch to accomodate it, which is nifty.
Also, look at the CSS2 max-width property, which allows you to say "I want my page this width, but if the browser window is smaller, squash it in!" ...pretty handy in my opinion (but don't forget the degradation in <=IE6!)
Keep content on the left of the screen, unneccessary advertising and navigation on the right
if the page does get to a screen that needs horizontal scrolling, the part that the user is reading is on screen, the dross is offscreen (like this page) user friendly,
not ebay : navigation on the left, auction items offscreen to the right