I work at a theater -- we dress cables constantly. I use a simple technique to get a straight line and it doesn't take that long.
1) Tape down the first end of the cable in an appropriate location with a small tab perpendicular to the cable run.
2) Pull cable straight in the appropriate position.
3) Tab on the other end of cable (again perpendicular to the cable run). You now have a straight cable affixed to the ground.
4) Run a piece of tape the length of the cable. (having a helper stick their foot on it helps)
Works pretty well for me.