Sawhorses are one of those few tools so immensely useful that they've transcended individual preferences and become absolutely essential in every shop, everywhere. You probably already have a few; you need more. If you're somehow lacking even a single sawhorse, you need to build your first pair this weekend. These videos should give you a good idea of how to go about it:

Build a pair of simple sawhorses by Steve Ramsey

How to Build a Sawhorse by Craftsman

A Japanese-Style Sawhorse by Journal of Light Construction

How to Build a Sawhorse by expertvillage

How To Make a Folding Sawhorse DIY by epicdiy

Collapsible Sawhorse by Carl Jacobson