Here are a few of the more common methods that people use in steeping fluids:
The One Step Process:
Take a new bottle of fluid, remove any outer wrapping, then store it in a low light (preferably in a box or drawer in a cool room) for a few days or up to a week or two.
The Two Step Process
Open the bottle, removing the cap and top piece. Set the bottle aside for anywhere from a few hours to a day.
Store the bottle for a period of time, as in the one step process.
The Heating Process
Get a container of hot (not too hot, and definitely not boiling) water.
Open the bottles of liquid you want to steep, removing the cap and top piece.
Set the open bottles in the warm water. Let stand until the water is room temperature.
Dry off and re-cap the bottles, and then store as in The One Step process until ready to vape.
There are literally hundreds of variations on these methods using things like coffee cup warmers, warm dry rice, and a basket that holds the bottles of eJuice in a slow cooker turned on its low setting.
There is a post on Reddit that does show some of the effect of introducing heat into the steeping process has. Granted the post is not conclusive evidence, however it is more methodical in presentation than the majority of anecdotal information that is posted by many people.(I don't reinvent the wheel, I lifted this from crebralift.com