How is the Vapor of an E-Cigarette Produced?

An e-cigarette has two main parts: a tank and a battery.
At the bottom of the tank (as is the case with all Kanger tanks), is a small piece where all the magic happens. This piece is called an atomizer head, but more commonly, a coil.
The coil ( a.k.a. atomizer head) has a wick that absorbs the e-liquid. Wrapped around the wick is a thin wire (the resistance) that connects to the base and is heated by turning the battery on, pretty much like the resistance of an electrical kitchen.
The wick absorbs the e-liquid that sits in the tank and when the wire (the resistance) becomes hot enough it evaporates the liquid in the wick, and the vapor goes out the top of the coil through the middle tube in the tank directly to your mouth.

Getting the wick dampened with the e-liquid or "priming" the coil might take between 5 to 20 minutes depending on the type of coil. The single coils are faster to prime than the dual coils. If the e-cig is operated before the wick is well moist the coil could get burned and a not so good flavor will come out. When using new coils always let it sit for a few minutes before starting to vape. You can read more about priming a coil by clicking here: Priming a coil

Over time and use, the coil will wear off. You will notice a decrease in the amount of vapor and also a change in flavor, meaning that you need to replace the coil. On average, a coil lasts somewhere between 3 days to 15 days, depending on your vaping habit, the type of coil and the ingredients of the liquid or nic salt you are vaping. If you are changing e-liquid flavors you might want as well change the coil unless you don't mind the flavor mix until the e-liquid in the wick gets vaporized. 
Some e-liquid flavors are tougher than others on the coil. How long the coils lasts will not only depend on your vaping habit but also on the e-liquids you are using.
Because the vaporization process is not as instantaneous as the traditional combustion process of normal cigarettes, inhaling a vaporizer takes a little longer; it is a slower process; you have to vape slower than you would normally puff a cigarette, worth the wait when you consider that you are not inhaling hundreds of harmful chemicals produced in the combustion of tobacco cigarettes.

Happy Vaping :)