read the POH for the particular aeroplane and nail the correct speed.
Well, a hot button topic for me:
Which correct speed? The POH will state a speed for "best glide" (it's a certification requirement). That speed is the speed to fly for the least altitude loss per distance traveled. This is of course very important if you're over the water trying to make it to the coast.
However, another speed which you should consider will be the faster speed, probably not stated in the POH, from which you can execute a nice flare, and have a little reserve of energy in case you misjudged. The alternative may be a crunch, if you use your little energy reserve (stored only as airspeed) in an imprecise flare.
A place to look in the POH will be the speed stated for climb after a normal takeoff (not Vx). That speed (faster than Vx, and maybe best glide speed) will be the speed which has been demonstrated will allow you to make a gliding landing straight ahead following an engine failure (another design requirement).
If you're keen, practice a full power off landing from circuit altitude at the "best glide speed". It can be done, but you're flare best be very well timed! Too early, and you'll crunch, as the aircraft, though pitched up, will not have arrested the descent. Too late, and crunch, because you did not arrest the descent.
I did this testing in a Cessna Grand Caravan, and it was very scary, the runway sure comes at you fast! However, to support the original theme, selecting coarse pitch, and further feathering the prop (which can be done with the engine running in the Caravan) made a terrific difference in the glide, and the POH so directs for that type.
All of this is definitely a practiced skill, just remember the factors associated with shock cooling an engine, if you're going to glide.