The amount of juice that the atomizer coil can vaporize per second is limited by the size, or surface area, of the coil.
> Feed the coil too much juice, and the excess juice will cool the coil, reduce the amount of vapor being produced, and usually result in an excessively moist hit with little to no exhale vapor. (This is what will typically happen when you've added too much juice to a cart, or haven't waited long enough for the juice to get well-absorbed after dripping into the battery-end.)
> Feed the coil too little juice, and the results will be a light and dry vapor, an over-heating coil, and, if continued, the foul taste of a burning atomizer blanket. (This is what will typically happen when you are either sucking too hard or have too little juice in your cart; but it can also occur when the useable life of a cart is reaching its end.)
> Feed the coil as much juice as it can vaporize - and not a droplet more - and what you will receive is the maximum amount of vapor per second that the coil can produce.
Since the coil does not stay heated (or lit) between hits, the quick, stuttered primer puffs that you'd take when first lighting an analog are basically the same sort of primer puffs that you want to take every time you go to take a hit from the Nebula. For, not only is there no point in initiating your inhalation hit until you have confirmed that a good vapor is being produced, but, in addition to heating the coil, the primer puff stage is also the time you want to quickly vary the force of your draw until you find that force that is producing the right flow of juice. The required draw force will vary, but a soft and slow draw will almost always outperform a hard and fast one; and this is perhaps the trickiest thing to get used to.
Another factor in good vapor production is the volts being put out by the battery. A fully charged battery will put out about 4 to 4.2 volts; but, by time the battery light is flashing for a recharge, it will have been putting out only about 2.75 volts. A decent vapor can be produced anywhere within this range, but the best and warmest vapor is most easily produced within the upper half of this range. This is why I tend to change my batteries often (every 1.5 to 2 hours). In fact, due to the blanket-burning dangers of running a cart low on juice, I change both my battery AND my cart every 1.5 to 2 hours. This way, I am enjoying an optimum amount of juice, volts, and vapor, almost all the time.