OK, I don't know how wise I am, but I probably qualify for the old part...

Break up your pedal stroke into 4 very rough components - think of it like a clock (NOT a digital clock, for all you kids out there!)

1. Push down with quad (we all have this one mastered) 2:00 to 4:00
2. Pull back like you are scraping mud off of your shoe 4:00 to 8:00
3. Pull your heel towards your butt (8:00 to 10:00 - this is the hamstring grabber!)
4. Push across the top 10:00 to 2:00.

OK, here's the part that puts it all together..

Picture the motion coming from your hip - your hip is the main pivotal point. This will help you visualize and use all of your power. Compare it to snapping a kitchen towel. If you hold the towel in the middle & snap it, you won't get as much "oomph" as if you hold the towel on one end & snap it. Same with the pedal stroke. If you picture it as coming from your knee or quad, you don't get all of the power that is available to you.

And, since we all have oodles of time on our indoor trainers or spin bikes, do one legged drills. This really helps cement the feeling of a full pedal stroke. Try doing one leg for 30 seconds & the other leg for 30 seconds.

As an aside...

If you're in the weight room right now (and aren't we all? ) working legs, try to do your exercises using one leg at a time to even out your strength. For example, I do laying down hamstring curls using alternate legs... left, right, left right. Same with lunges, leg extensions, etc. It's a little tough to do squats like this - you better have good balance! But on many of the machines, you can alternate legs - left right left right. Don't do all on one side & then all on the other. You want your brain to register "left then right then left then right" just like pedaling.