At one-time smoking, meat was done to preserve it so that it would have a longer shelf life. That was before we had freezers or refrigerators. Now days smoking meat is more related to barbecue and it is done to add flavor and to tenderize meat. There is nothing quite like smoked barbecue.
To do smoking right you need hardwood such as hickory, oak or apple. Down south smoked barbecue is almost always done with hickory. Some people will tell you that you can smoke meat with anything but I would not try to smoke barbecue meat with pine, for example, or just any old wood. Actually, I would only use apple or hickory and it would depend on what I was smoking. For example, ham, bacon, fish, turkey could be smoked with apple wood, but pork, beef, and venison I would only use hickory.
For smoked barbecue meat, temperature control is very important, you want the smoking process to go slowly so the smoke penetrates the meat and tenderizes it. The temperature should be between 200 and 220, this makes the process go slow enough but heats the meat enough so that it can be safely eaten.
You want to position the meat in the smoker so that it is surrounded by the smoke and you want the smoke to be moving at all times to prevent creosote from building up on the meat, creosote will make the meat bitter and unfit to eat. A well-designed smoker will have a way for the smoke to escape so that there is a steady stream of smoke around the meat as the smoke rises and escapes from the smoker. In this was the smoke will be constantly moving with new smoke coming from the wood as it burns.
Like anything else making smoked barbecue will take some practice to become an expert, but once you get the hang of it you will love the meat you smoke.