Figuring out the measurements for your site layout
When deciding on a site layout, what decisions help you decide on what units to use like pixels vs percentages vs viewport vs... etc. Just curious because I'd like to build a simple layout as place holders but I get stuck on what units to use in what situation and positioning elements where I want them. I can get a very basic layout on paper and using background colored attributes but get stuck on units to use. Hope to get some great feedback 
