Throttle only, NEVER mixture since the engine can, in fact stop turning and turn a practice into an actual emergency.
Be a minimum of 2 mistakes up, 2,500-3,000 AGL is good for most.
Find a stretch of road or landmark feature to simulate the runway since that is equally as important as the recognition of engine failure and reaction, you need something on the ground to refer to. Key is to have some sense of length/distance over ground, since you don't want to end up short or overly long - ideally you should have 'ends' of the runway by ground reference (tree, house, intersection, etc.) but obviously not a maneuver you should be doing over other than sparsely populated ground.
When doing this exercise personally and with pilot friends we set our hard deck altitude and slow down Vx or slightly slower in level flight, once over the simulated runway and at your best estimate of a reasonable take-off point apply full power and assume your normal climb attitude/speed.
At your target failure altitude pull power to idle. FAA and most instructors say it will take 3-5 seconds to realize and acknowledge you have had an engine failure. I believe that is nonsense since I am very sensitive to sound/vibration and the seat-of-the-pants aspect of power but I still allow for a 3-second delay/deceleration before I pitch over. Be forewarned, it seems like a VERY long time when you practice it.
Pitch over aggressively for best glide speed and start the turn immediately, practice both directions. I use a lot of bank (~60 degrees) and a fair amount of rudder but try to keep the wings unloaded, the objective is to get the nose around quickly and rudder can help within reason - avoid the urge to pull hard.
You will be nose-low and pulling/kicking for a pretty substantial rate of heading change - I don't think I exceed 1.5 G but most planes don't have accelerometers in them, when I practice in the Yak I will be able to tell for sure but you do not want to load the wings up at slow speed.
Maneuver to line up on your reference runway with enough speed for a moderate flare and see how you did. Best to do with another pilot, and trade-off so you both can monitor traffic as well as how well you do with respect to your simulated runway.
In a friend's Grumman Traveller, pulling power at 500' above our hard deck we would have close to 200' to go when rolling out after 190 degrees of turn - aggressive roll in, hard left or right rudder with between 3/4 to 1.5 G, pitching for best glide.
The key is to always have an abort point for every takeoff, and to commit in your head before every takeoff that you are crashing straight ahead if you have an engine failure below the altitude you have repeatedly shown you can make a reliably safe turn-back.
In formation flying we brief every engine-start, taxi-out, takeoff, training evolution, return-to-base, landing and taxi-in - it is a great practice for anyone because it helps to get clear about decision points. I recommend everyone brief the takeoff, and engine failure options, at least in their head prior to each flight - keeps the whole thing fresh.
'Gimp