Everything together factors in to vapor production. The main things are VG ratio, and Watts being pushed to your device. Also having a clean coil and wick helps. To increase your Watts you'd increase your voltage and/or reduce your coils ohm rating. BUT YOU HAVE TO WATCH YOUR AMPS AND BATTERY AMP LIMIT SO YOU DONT BLOW IT UP!
Another important factor is airflow. The more air you have flowing over your coil the more vapor you get...to a point. Once you get to the point of too much air you're inhaling more air then vapor and you'll get a weak hit every time.
So to sum it up, Increase your VG ratio, Run your setup with more watts(Safely!), Make sure you have decent airflow, and keep a relatively clean coil and wick. I'm blowing respectable clouds at 2.6Ohms and 5.5Volts with an 80%PG mix, but I very carefully make sure my battery doesn't start to overheat, and if I'm chain vaping I reduce voltage to around 4.8V to reduce the stress on the battery.
I'll post a pic in a minute of my vape with 80% PG mix and just using a carefully tuned and monitored cheap setup. Keep in mind I have no life so carefully monitoring my setup and maintaining it gives me something fun to do, but can be time consuming.