Fortytwo blades, I for one would like to hear more about proper machete techniques... it might be fodder for anew thread.. I know some cate like Pict and BTD might also have some advice to offer.
It's as the old saying goes...it's all in the wrist!

Begin with your arm held held close with your hand near your shoulder. You should be gripping the machete with only the first two fingers and thumb, firmly but gently. As you snap the arm forward towards the target, let up with the first two fingers while squeezing instead with the bottom two. Think of the machete as "rolling" along the palm through the squeeze of your grip. The angle of attack should always be diagonal, even if shallowly, but a 45-60 degrees seems to work best for me. The more against the grain you go, the harder it is for the blade to penetrate deeply. Then make a similar cut from below. Begin from the high position as before, but combine with a wrenching motion during the through such as to come from a low angle. You should have now removed a very large chunk of material.
Limbing trees is fastest with a machete, as far as I've seen. When there are several branches in line with each other you may take them all out in one swing. Using the same throw, but horizontally, cut in the direction of the first branch as if you were aiming to hit the last one with a powerful blow. You ought to plow straight through all of them (we're talking 1/2"-1" limbs in this instance) Don't be afraid to put some muscle into it!
If the limbs are thicker than 1", or you have difficulty cutting them in one strike, cut at the underside of the limb as close to the base as you can manage. Use the vertical throw on this one. Few branches, even 3" ones, can stand up to more than two or three of these cuts, and most branches will give in after only one.
When clearing saplings take them out with a single vertical throw. Once they've fallen over you may hook the crotch of one of the branches with the back of your blade and haul upwards and back to throw the sapling behind you. With minimal practice you can easily control the force and direction of your pull so that all of the saplings you clear land in a single brush pile away from the work area! It's important that you NOT cut too close to the base for this technique or else the sapling will not fall in a convenient manner. After removing the bulk of the tree, follow up with a downward cut to the base to neatly trim the remainder away.
For clearing lighter targets like brambles, weeds and grasses your blade must be extra sharp or the targets will merely bend out of the way. If you have a machete with an upswept blade it may help to sharpen the last five inches of the spine at the tip to create a hooked cutting surface. If not then it's not a big deal, but it will be a little more difficult. Use powerful plowing strokes to sweep back and forth close to the ground where stalks are the strongest and least likely to bend. Keep the blade angled slightly upward to provide tension. For brambles keep your distance and work at the stalks from the top of the growth down using strikes from below. You'll work your way down to the base level relatively quickly.
Because of the rolling snap that should be used with a machete I do not often recommend using a lanyard. Rather I would simply cease your work if your hands and forearms get tired. A smooth but unpolished handle will usually work best as it will not abrade the hand but not be so smooth as to cause rubbing and blisters.
There are a few other things I haven't covered but those tackle the bulk of what you're likely to be doing with a machete as far as clearing is concerned. There's a lot of handy things they can do around the camp as well, and a few other clearing techniques, but I'll save those for another post.