When you decide to upgrade to a more advanced mod suck as Kanger Subox, Istick etc that are designed for sub ohm vaping. In basic terms sub ohm means you get a whole lot more vapour production. There is just no comparison if you are currently using an ego, pen style e cigarette. With pen style e cigs the wick is very small and cannot feed the element fast enough to get a very large vapour and because of this are prone to burnt hits, sub ohm coils are far larger and designed to absorb many more times the amount of liquid and thus can keep up with demands of the mod without burnt hits which nobody wants.
An easy to manage sub ohm tank is the Aspire atlantis with large and small air holes depending on your style of vaping ie mouth to lung or direct lung inhale. this will fire to 30 watts happily. The only downside to the atlantis is you have no rebuildable deck included so rely on purchasing coils.
Kanger subtank. As the aspire but with a rebuildable deck so giving the best of both worlds.
Atlantis 2 is only suitable for 50watt plus mods that allow such low firing with the 0.3 ohm coil but does also take the 0.5 coils enabling them to be used on lower devices. Superb clouds
Aspire Nautilus is more suited to a user who wants more vapour but not sub ohm and the largest vapour production. It will provide vapour production a lot more than a pen style but not as great as sub tanks and offer great flavour too.