This one is applicable to charcoal
http://amazingribs.com/tips_and_technique/zen_of_charcoal.html
Build a small hot fire. You want to see flame. Fires burning in the 650 to 750°F range in the hot spots burn off the impurities that can becreated in an incomplete secondary combustion. That means that you need a lot of oxygen so you want your exhaust vent open all the way. The hot air rising through the chimney will draw in air through the intake vent. You will probably want it open wide or close to it. Low smoldering wood creates dirty smoke
Allow the fire to get rolling and allow the pit to warm up. Start the fire well before the food goes on. Warm the walls of the cooker.When a recipe says "preheat" your cooker, do it. Adjust your airflow and get the temp, fire, and smoke stabilized. Be aware of the weather. It is harder to get blue smoke in cold, rainy, or windy weather.