How to reduce the landing roll distance
1) This does mean you should keep the nose up as long as possible, increasing the angle of attack when you are behind the drag curve increases the drag the wing produces and uses the elevator as a spoiler in effect. If you have done a full stall landing pulling up cannot get you back into the air, but if you land with extra speed pulling up could mean you start flying again, so you should only use this technique if you are sure you have a low enough airspeed. Good technique is not to yank the stick back, you pull it back while paying attention to the "feel" of the airplane, if it seems to want to fly again ease off on the back pressure. 

2) Retracting flap after landing decreases lift and puts more weight on the wheels, making the wheel brakes more effective. It does decrease drag, however your wheel brakes are much more effective at slowing the airplane than drag from the flaps.