Sub Ohm Tanks
If clouds are what you're after, sub-ohm is the way to go.
Sub-ohm tanks are built to handle coils rated at less than 1.0Ohm, and vaporise much more e-liquid per puff than a more conventional tank. Using direct lung coils, they offer very little resistance on the draw, meaning much greater airflow (like sucking on a wide straw). It's advisable to step down your nicotine strength when working with sub-ohm coils, as the increased amount of vapour produced per puff will quickly become uncomfortably harsh.