Right Shoulder - This is the most important position to master.  Almost everything stems from right shoulder, sometimes abbreviated RS.  Your left hand goes over the bottom stopper and your right hand grasps the flag at the tape. (The place right where the silk stops and it's bare pole.)  Now, no matter how short a you are, or how long the pole, your left hand is directly covering your belly-button, or the area right were your belt buckle would be.  The flag should be straight up and down and in the center of the body.  A good way to check this, is to make sure that the flag is right in front and in line with your nose.  When this is all done, the right hand should be just above or right at forehead level.

Left Shoulder - This is the same as RS, but the hands are switched.  However, this position is not very common.

Right / Left Slam - I'll describe this as Right Slam, abbreviated RSlam.  There are two ways to think about this.  Start at RS, and just bring the flag down to your right until the silk tip is pointed at the ground.  Like you're slamming it towards the ground. (Hence the name)  The other way is to put your left hand at the stopper and your right hand at the tape.  Hold the flag at a 45 degree angle up from the ground.  The flag should cross your body like a diagonal.  Your left hand should be in front of your left shoulder and covering over top the pole.  Your right hand should be a couple inches out from your hip and palm facing up to the sky.  LSlam is the same as RSlam, just switch your hands and the flag is on the other side of the body.

Right / Left / Front Present - Start out in RS and push your right arm straight forward until it is completely extended and parallel to the ground.  That is a front Present. (FP) Your left hand DOES NOT move from your belly button.  Make sure you're not hunching over or burying the stopper in your stomach.  Left Present is pretty much the same except the top hand moves to the left until it's MOSTLY extended.  Obviously one cannot extend their arm all the way without causing pain, or throwing off the angles in comparison with others.  Go until your elbow is in front of your chin.  Now, Right Present (RP) is the hardest to keep clean.  Try to keep the flag directly in front of the right shoulder.  If it doesn't cross in front of your shoulder, you're probably going too far.

Flat - This is the easiest position.  It's pretty much just the way it sounds.  Start at RS, and bring the flag down until both arms are extended down.  Keep your arms loose, and make sure the center of the bare part of the pole is in the center of your body.  That way your arms are out from your body at equal distances.  This can also be modified to eye level, where the flag is parallel and directly in front of your eyes.

Okay, now that we've got that covered, how about some spins?

Drop Spins - Despite the name, you don't actually "drop" the flag. (although my fellow flaggers might disagree :) Start at RS.  The flag moves counter-clockwise for this spin, since you are starting at RS. (This can also be spun clockwise if you start at LS, but that's a little more difficult!)  Okay, take your left hand off the stopper and let it hang at your side for now.  Move the flag counterclockwise until the flag is straight upside down.  As you bring the flag down, also bring your right hand down.  By the time you get your flag is upside down, your right hand should be in front of your belly button, right where your left hand used to be.  Now put your left hand flat out in front of you.  Your palm should be facing the ground.  Turn your hand 90 degrees clockwise until your thumb is pointing to the ground.  That may feel funny, but that's how you know you're doing it right. Okay, here's the hardest part.  Keep your hand palm facing to the left (thumb down) and grab the pole.  But you MUST grab below your right hand.  Both thumbs should be pointed away from you.  Now take your right hand off and let it hang by your side.  Keep the flag moving counterclockwise until it returns to being right side up.  Grasp it again with your right UNDER your left.  Guess what?  That's a drop spin.

Tips on spinning:

-Two words: Down, Up.  As you spin, say down, up, down, up...etc.  Trust me, it's a big help for beginners.
-Is your flag slowly rolling up?  Watch the way you're grabbing the flag...you are most likely twisting your wrists too much.
-Please, please, please make sure you are always grabbing under your top hand.  Stop yourself and check every now and again.  It's a difficult habit to break if you learn it wrong.
-The more you practice, the cleaner these will become.  Start off with a set of 50 spins and work up to two sets of 100...one set from RS, and if your are felling confident, 100 from LS.
-Make sure you're spinning at your waist.  If you spin too high up, you are making it much harder on yourself and wearing out your arms.