Timers are a good idea. Often the pilot will experience a compressed or distorted sense of time while flying. So its very difficult to judge 10 or 15 minutes. And waiting until the engine coughs is a bad idea. By then, there might be someone on the field. Its better to call the runway and land with enough fuel remaining to delay for 1 minute, especially at larger events.
However, your deadsticks are great training.You can still simulate them from time to time. Just randomly cut power and pretend the engine has failed. Its not 100% realistic. Airplanes actually glide better when the engine is dead rather than at an idle. But its close enough for practice.
Landing with the engine running does take a more sophisticated technique. You aren't simply controlling your energy with elevator and your path. You will use your throttle to control your rate of descent. You will use your elevator to control speed. So once the airplane has been slowed down, the elevator input changes very little, almost none at all. At that point you are controlling the "sink rate" with throttle. If it looks like you will be short, add a small about of power. It might just be a momentary increase of power and then return to idle. But the adjustment is made with throttle and not elevator. The elevator is used again when you are flairing to land. At this point you are inches from touching your wheels to the ground. Power is completely off. You are trying to hold the airplane off the ground as long as possible and you gradually squeeze in more and more up elevator. Then, Errrk, you've landed. Some heavier airplanes will actually require that you carry a click or two of power all the way until touch down.
I hope this helps you. Good luck.