If you're bouncing, your saddle height may be off. I think it's an indication that your seat is slightly too high- but I'm not positive. Maybe mark it, and try dropping just a little bit (less than a cm at first). The other thing to do is concentrate on your pedaling form - pedal circles, don't "mash" down and then do nothing when the pedal is coming up. Someone who knows bikes could probably look at you and tell what you're doing. Also - maybe try higher cadence on the flats - until you're used to it.

Good luck - and ignore the brother.

CA