People are concerned that you do your research because the best way to get huge clouds is to get a mech mod and build sub ohm (resistance is less then 1ohm) coils. Regulated devices are designed not to fire coils that are below a certain resistance for safety reasons. With a mech mod, you can bypass that safety feature as there are no electronics to stop you. It will fire whatever you put on top, whether the battery you are using can handle it or not. It is important that the battery you are using can handle it, or it can over heat, vent, etc... Not a great situation.
For cloud chasing, you'll probably want a dripper with a deck large enough to handle multiple coils, which will also aide in lowering your resistance. The lower you go, the faster the coils heat up and the hotter they get, hence more clouds. To prevent simply burning the liquid and wicking, you want the most airflow possible. Many drill out the existing air holes to a larger size, and position them right by the coils. Also, you will want an e-liquid with a higher VG ratio, as VG produces more clouds then PG.
For batteries, you want a high drain battery capable of handling as many amps as possible. I hear a lot about the green Sony batteries.
Invest in an ohm meter and a multimeter as well, so you can check how much power is left in your battery (going too low before charging is bad for the battery) and check the resistance of any coil you build. The lower the resistance, the more clouds you may produce, however, it is more taxing for the battery and can be dangerous if you do not have the proper equipment and knowledge. I do not, so I don't sub-ohm.
