I purchased this
trekking pole DVD and, wow, what a difference when they are used properly. If you have a friend who has this DVD, ask to borrow it. Maybe there is a YouTube video out there.
In a nutshell you want to adjust your poles. Adjust the upper barrel (closest to the handle) first; then the lower barrel if you are a tall person (or a yeti) to where you lower arms are almost parallel to the ground (plus or minus--whatever is comfortable). Take your hand through the bottom of the strap (soft side of the strap inside) and up and grip the handle between your thumb and forefinger (web of your hand). Adjust the strap. When going uphill, plant the poles behind you and push off while still maintaining the grip (great tricep workout BTW if doing correctly). Keep the poles moving forward and back shoulder-width apart and not flailing all over the place putting you and other members of your party in peril. You want to hike with your party, not skewer them!
Don't squeeze on the grips (fatigue factor) because your strap helps with the leverage and the strap is your best friend. Never place the poles in front and then pull yourself up. Waste of valuable energy results in fatigue in your shoulders.
On training hikes, I have the option of wearing gloves. Preferred gloves of choice in warm conditions are cycling gloves-the same gloves Lance Armstrong uses!
For the downhill, the DVD says to extend the lower section further out and place out in front like little antennae and plant in the ground in front of you and then walk forward. Well, my experiences dictated that I don't like this technique except to extend the poles so I can gently ease myself down a step or a boulder. Saves the jarring on the knees. I figure, if I slip and fall on my backside, I got a pack to cushion the fall.
They are excellent for balance especially during the wee hours of the morning when there is nothing but your headlamp shining the way and you come upon those darned wooden logs on the MWT.
You can purchase baskets for your poles. They come equipped with a small basket for rocky trails. Larger baskets are used for snow travel or if you are hiking sand dunes. You can even hike without the baskets. Caveat: without those baskets you could run a chance of ramming your pole into a crack and break your stride and ruin your concentration and worse yet, break your poles. So the baskets are good protection against this.
Sometimes you may experience a pole that may not lock. Simple remedy is to extend the the problem section all the way out. Twist (or turn) the section slightly in the "tightening" direction and collapse and then turn again. It should catch. If not, repeat the process. Also, it is good to remember to wash off your poles after use and towel dry them. Dirt and debris may be the culprit in poles not locking. Let the rest air dry.
As an option, you may want to purchase rubber tips for aethetic purposes if you are sick and tired of all the clicking you do while you hike. Also prevents accidental skewering.
Speaking of skewering, when I am not using my poles, do I carry them with the points front or back? It is a matter of preference. Just remind members of your party to give you anti-skewering room.
As I mentioned in another thread, I wrap duct tape around the base of the handle for those little emergencies such as hot spots on the feet or I need a sunshade on my nose because I forgot to pack the sunscreen. And, of course, if my boots blow out on me, I hope I have enough to repair.
Also, I pack along a couple of straps in case I need to make a splint.
They also make great tent poles or a drying rack.
Too bad the handles aren't hollow so you can carry a snort or two during those backpacking nights.
Poles are not recommended for roasting hot dogs or marshmallows.
Don't know of anyone fishing with trekking poles. Guess one can make an attachment. Hmm...
Some people do not advocate the use of poles saying they tear up the trail. True in some respects. But I would rather "tear" up the trail than tear up my knees.
Do not pack your poles in your carry-on! You will make one TSA hiking enthusiast very happy.

Since reading the thread (thus why I am editing), carbon fiber poles may be the preferred type of pole for use in the Gr8 Yd Opn. Lightweight and strong and they do not act like lightning rods during a thunderstorm.
If you purchase your poles at REI, and you use them and they break on you, you can take them back for a full refund or you can get another pair without any problems. 100% satisfaction guaranteed. Now there is an instance if your bought your poles for $110 on sale, and they break on you and you have to exchange for a new pair they are now regularly priced at $149.00, you will have to pay the difference. Why? I've argued until the veins burst in my brain housing group. What the heck! More for my dividend.
I am sure other stores have the same policy, but you have to bring in the proof of purchase. At REI you don't need the receipt, but if you remember when you purchased them, that helps.
There, I hope this helps.
Have fun.