The REI video
@Mason linked to is how I used to do it. But as
@Sweetfancymoses suggests, I sometimes found that the slip knot didn't release easily, especially when I really cranked some tension into the trucker's hitch..
So now when I create the loop for the slip knot, I add an extra twist of the loop before feeding the bight through. Definitely helps the slip knot release more readily.
When using thin line like a tarp ridge line or parachute cord, I also find it useful to run the working end through the loop twice (after coming around the tree or other tie off point) before cranking down on it. Some folks call this an "automatic" trucker's hitch because the second wrap through the loop automatically prevents the tension from being released while you tie off (no need to pinch all the lines together).
By the way, I don't think I'd ever use a trucker's hitch on a tent guy line as is shown in the REI video. I'd be afraid the mechancial advantage of the trucker's hitch would rip the guy line attachment point right off of the tent fly. So for guy lines I just use a taut line hitch. Easily adjusted and holds sufficiently but there's no mechanical advantage.