The white smoke/blue smoke issue doesn't really occur with charcoal; it occurs with the added wood to charcoal for smoke flavoring. Charcoal is a wood product created by heating away most of the moisture, resin, and other impurities leaving mostly carbon. This is why a piece of lump charcoal weights less than the same size piece of wood, and why it burns so much cleaner than wood.
Some charcoals have additives to make them burn more consistent, and then with smokers with water pans; vapor can be misconstrued as white smoke. Some charcoals can absorb moisture if they are stored in an outside location. This type of smoke is mostly moisture escaping from the cooker and probably is not from poor combustion.
The simple way is to tell is to follow your sense of smell. Bad smoke is overpowering and smells bad. Good smoke smells good and not overpowering.
Sweet blue can be seen even when it's "invisible" but you have to get the right angle of light on it. It's very thin, and wispy, and almost invisible.
Follow your nose rather than your eyes.
Humphrey's DownEast Beast W/BBQ Guru