Although I've retired from an industry that required installing thousands of compression fittings with service pressures as much as 1,200 lbs. pressure and as little pressure on home plumbing jobs, not a single person other than my former employment superiors and the written instructions on the box has ever acknowledged this fool proof way to do it.
On installs with new ferrules, place the nut on the tubing, place the ferrule on the tubing, insert the tubing into the fitting until it bottoms and stops. Run the nut up with your fingers until it stops. Now while making certain the tubing remains bottomed in the fitting tighten the nut 1 round, that's right, 1 round while holding the fittings mid section with the second wrench ( a backup ). Yes, that's why that fitting has a Hex shape in the center.
Now here is something for some novices. If you are unable to make 1 complete round because of obstacles in the way, 6 hexes = 1 round.:wink2:
If you are inclined to apply some king of mucky puck crap to make it seal better, grab your tin or tube of plumber's grease, 3 in 1 oil or singer sewing machine oil and lube the threads little. Being this is a swaging operation I usually lube the ferrule also.
Note: this is for home plumbing and not for industry fittings such as Swage Lock, Parker and others. They have their own instructions which usually recommend 1 round plus 1 or 2 hexes more.
Or you may like to confer with an engineer.