One of the most common problems with e cigarettes is flooding. This can be caused by a number of factors including the e-liquid your using. E-liquid needs to travel along the wick to the coil, where it is heated until it vaporizers. In the picture to the left you can see the different parts of a vivi nova tank. Note were the wick enters the atomizer and also that the atomizer is hollow. If too much e-liquid enters the atomizer, flooding will accrue. Each different blend of e-liquid will have a different viscosity and so the thickness of the wick should be adjusted to suit. Generally atomizers can be disassembled and re-built. If your e cigarette is flooding due to the viscosity of your e-liquid, then adding or removing part of the wick will solve the problem.
The other common cause of ecig flooding, is the user drawing or inhaling from it with too much force. This will cause the e-liquid to be drawn into the atomizer too quickly. When vaping it is better to take long slow draws from your e cigarette. As opposed to a regular tobacco cigarette. If you find that you are flooding your ecig regularly due to excessive drawing on it. You could consider increasing the strength of your e-liquid.
The angle at which you vape from can also lead to flooding problems. This is more apparent when you are using the top heating coil, such as the vivi nova tank. As opposed to a bottom heating coil such as is used the the protank.