I begin heating the bowl and hitting.  Here I'm fairly careless on my hit rate, though still slow.  I'm trying to rapidly heat the bowl without igniting the changa.  I am moving the torch up/down, in/out of that bowl and when it's in, I am moving it in a circular action, round and round, then up, then down with circles, then up, etc.  Somewhere here vapor begins to flow.  The moment I see vapor I slow my hit rate and as soon as the pipe appears full I stop. 

In between the two hits I am not applying the torch to the pipe.

I take a very quick breath (sometimes), exhale what air is left in my lungs, then begin hitting again. Again, up and down and circular and a slow hit but this time everything much much slower on the actual inhale but a bit quicker in my action with the torch (the pipe is now warmed up).

I hold a minimum of 6-10 very slow counts (one one thousand, two one thousand, etc.), then exhale.  If I do not have the effects I desire at this point I immediately take a second hit, but without first half filling the pipe - I just take the hit.

Regarding residual vapor in the pipe - yeah, this happens to me too.  When it happens I do my usual procedure, but right after, just finish off that vapor.  In order to try to prevent it, I remove the torch from the bowl fairly early on in my hitting procedure and just continue without fire, inhaling slowly.

Hope this helps . . .

Peace & Love