I advocate keyboard shortcuts to improve your navigation speed across your Mac; but there are times when your workflow relies on multiple windows to gather or review information.
Apple’s OS X folder buttons provide “close” “minimize” and “full screen” which work great but for more control on arranging and sizing windows so that they tessellate on your screen I use Moom
Moom by Many tricks is a great Mac utility that provides that complete and customizable user control. Sizing and arranging windows to suit your specific needs is quick and simple. This app has saved me countless hours to date…try it for yourself.