yeah you can just mix it and vape it right away. You dont need to steep it (leaving the juice in the dark etc), the people who do those are the eliquid flavor fnatic people, i think they are kind of kookie

. If you vape it right away, the flavor basically tastes exactly how it smells/tastes right on the spot, after a while when you leave the juice around sitting there the flavor changes, could be for the better or for the worse, but if you vape it right away it tastes fresh just how the flavoring smells. The benefit of this is, after you mix it and try to vape it, you say to yourself "oh that tastes good, but i think id like a little more flavoring", then you just put more drops of flavoring and try it again lol. No waiting around to see if it works out or not a week later when you vape it. You could just make a small batch of 5ml, try it out and if it taste disgusting just throw it out.
one thing id suggest if you do try this - say you are buying a peach flavoring, try peach from two different companys, some company make better flavoring than others. I also would reccomend you just buy small amounts of flavoring like 10-20ml bottles or less even - the flavoring is strong and most of the time you dont use it all, just order a bunch of different flavorings in small amounts, then when you find out what you like you can make a bigger order of the flavoring next time.