Never use the paddle for propulsion or steering.

Shoes off. Bare feet grip the platform. Plus, it's easier to swim if
(god forbid) you fall in the river.

Stand well back on the platform; that way the side of the boat
interferes with less of the stroke.

Get the pole well out of the river before turning it upright for the
next stroke - if the tip gets in the river, you can't do anything with
it.

Drop the pole through your hands. This is the single most important
thing. If you shove the pole down hand over hand, by the time it
reaches the bottom the tip of the pole is well behind the boat, and
you can't do anything but pull it up again. Once you've got it
upright, just open your hands (not all the way :-) and let it fall.
If you're in a hurry, you can actually throw the pole down towards the
bottom of the river.

The other part of that is to anticipate what the movement of the boat
does to the position of the tip of the pole as it approaches the
bottom of the river. If the boat's not moving, you want to angle the
pole towards the rear; at some speed you can drop it straight down,
and when going really fast you aim it forwards because the tip will
still be behind you when it makes contact. These factors are
exacerbated by not dropping the pole; hence the classic tourist
"circle" maneuver. If the back of the boat's going to the left and you
just put the pole straight down, the tip ends up to the right of
you. Now when you push you just make the back of the boat go leftwards
faster.

You do less work if you lean backwards on the pole, rather than
leaning forwards and then shoving backwards.

Steering tip one; you can use the pole as a rudder after the stroke's
finished. 

Steering tip two; you don't need to do _that_ if you separate your
hands on the pole; then you can exert torque on it while it's still
lodged in the bottom by moving the top and bottom hands in opposite
left/right directions.

Steering tip three; you don't need even to do _that_ if you can choose
your tip impact points well enough to give the right amount of
sideways thrust.

Punting one-handed; steering methods one and two don't work, so you
need to be good at number three. You've _got_ to drop the pole through
your hand but you should be doing that anyway. You need to be able to
throw the pole forwards through your hand after the stroke, then twist
it upright with your wrist. If the bottom's shallow, you need to be
able to take half the stroke and yank your hand up the pole in a
tearing hurry to take the rest without dropping it.

If the pole gets stuck, twist it vigorously and bend your knees,
dropping you down under the pole; aim to brace yourself between the
pole and the platform so that you are pushing it upwards not pulling
it forwards; if you pull it forwards you risk going in backwards. Keep
twisting; twisting and pulling at the same time is very effective.
Remember that it is better to let go of the pole than go in with it -
either way, the punt will have to retrieve it.

If you do have to swim with a pole, grasp it in the middle and press
it down into the river. Now it wants to buoy you up, out of the water.

Do not hold the pole upright too close to bridges; some joker may be
"fishing" for punts. In general you do not have time for one last
stroke before a low bridge - the pole's other end sweeps forward as
you take the stroke.