Tightening a nut too much Often guidance will be given to tighten a nut to "20 ft. lbs. (27 Nm)" or something along those lines.

What's the best way to ensure you tighten things up, but don't over-tighten? 

Is there any way to do it other than by measuring the force?  If measuring, how do you measure?
You use a Torque Wrench.  You set how much pressure, and when you tighten to that pressure, the wrench will "click" and not tighten the nut/bolt any more.