Andrew Skurka's guy line tensioning system. I always used a quick-release hitch[1] instead of a bowline and a taut line hitch[2] instead of a trucker's hitch -- but the trucker's hitch looks like it would get and keep everything more taut.

1: like a halter hitch, https://en.wikipedia.org/wiki/Halter_hitch
2: http://knots3d.com/knots/en_us/4/taut-line-hitch