SPEEDboy
you can always grab your putter and work on making nice and easy strokes with it. just swing the putter like a pendulem back and forth like you would on a putting green

Eli
hit a tennis ball or a practice ball for short irons, and if you really want to get a good practice in, there are very inexpensive nets available. i know you didn't want equipment use, but they're cheap and very good practice

skyler
If you have at least a 9' ceiling you're backswing should never hit it (even driver). So what I do is much like boxers shadow box, I shadow swing my club. Find a Pro golfer you really like watch his swing on youtube or something along those lines, and go through the motion with it untill you fee comfortable with it. Then step outside and take full swings. I actually hit pennies into my couch with a blanket over the front to stop it so I can work on my coordination. Also if you have any type of front or back yard you can practice you chipping or flop shots. I have a mixture of big and small trees so I try and chip over the small one and land it infront of the big one. It takes practice but it helps trust me. Ive played less than a year and I went from about an 9-11 handicap down to a 4. You just need to be smart and cautious with your surrounding so you dont break anything because you didn't pay attention. But believe me it works. Also if you have an old club, take some ductape and some quarters and tape them to the shaft to give it some weight to increase your distance. Believe me I ACTUALLY do this and it helps. Hope it helps you. Almost forgot. To save you the trouble dont use anything lower than a 7 iron if hitting pennies. I made that mistake and over hit my stopper and about took out a window lol. Long irons work perfect.