Just a quick tip:
If you refill your own cartridges (a good way to save some money), then make sure you don’t add too much liquid at any time. Drip it in slowly until the wadding is thoroughly soaked, but without excess liquid on top. Then wait a couple of minutes to make sure the wadding has fully absorbed the liquid before you attach the cartridge to the cigarette. Never use ecigarettes with an empty cartridge – you risk irreparably damaging the atomizer