Proper Size
The handle on the hiking stick should be where your hand is if you are standing straight and your elbow is bent at 90 degrees. 

The height of the stick is up to you. Shorter sticks are usually lighter to carry and fit in your car easier than longer sticks. Longer sticks help you walk over uneven ground, rocks and walking downhill.

Proper Care
If your stick gets a scratch on it, you can lightly scuff the area around the scratch with a high grit (220+) sandpaper, steel wool or scrubbing pad. Then you can spray or brush on a coat of spar urethane. If your stick has an oil finish, you can use a rag or brush to apply another coat of oil. I use an exterior oil such as Bush, Teak or Danish Oil.

Dents in your stick can be raised by using water and a clothes iron. Put some water on the dent and let it soak in for a while. Place a piece of wax paper over the dent and iron it. The heat will cause the water to expand and lift the dent.

Proper Use
Your wrist should support your weight and your hand should move the stick. The wrist strap should go around your wrist and up through your palm. The strap can then be held against the stick between the stick and your palm. This allows you to put your weight on your wrist and forearm instead of just your hand.