Hi Meinxerces
Oliver hasn't exactly explained it right and it's not quite that simple. Firstly the wattage you throw at your coil depends primarily on 2 things, the coil's resistance (which you haven't mentioned) and what you like (which really is probably the overall deciding factor).
The higher the coil's resistance the lower the wattage. There are lots of guidelines listed for wattage ranges but those are simply other's ideas of what works best, for them presumably. Other factors also effect the wattage setting such as the type and design of the tank, the juice your using, your airflow setting, among others.
Trick is to find what you like as a power setting so you can set it and reset it to your heart's content. Don't expect it to stay the same. You may find yourself vaping at one setting in the evening but then changing that setting the next morning, same juice, same tank, same everything except how you are finding it to your liking or not.
Too low a power setting will usually give little vapor and be a very wet and gurgly vape usually with a very strong (sometimes too strong) taste. As you increase the power the gurgles turn to hisses and the vapor cloud grows and the taste gets less. Keep going and the taste begins to disappear as the clouds grow and the vape becomes drier & warmer. Keep going and the taste will go completely though the vapor clouds won't just keep getting bigger and the vape is becoming very warm. At the higher power levels you are now risking a dry hit where the coil has gotten very hot and singed the cotton. That will taste like a burning T shirt.
Somewhere in or around the middle is where you'll usually find your sweet spot but where ever it is its yours and likely no one else's. To find it you should start with a very low power setting say 5 or 10 w's and work slowly upwards. That will begin to acquaint you with how the varying power effects the vape. You will know when you've gone too far and the vape quality is decreasing and then head back down again until you find what you like. You can also play with the airflow. Generally less airflow means a tastier wetter vape while more airflow results in the opposite.
Have fun, experiment, play. If you do taste a burning cotton taste then your problem may be too much power, too little juice or too little airflow. Catch it quickly then normally no problem. Scorch it badly and you'll have to install a new coil. When you taste a burnt taste stop vaping immediately and either turn down your power, give your coil a chance to wick more juice, and/or open your your airflow up more.