I have a baseline drill that I do from time to time. Target is an 8.5"x11" sheet of paper, vertical (I usually tape it over CoM on a silhouette target). The drill is 2 rounds, in 2 seconds, from 2 yards, from concealment, both rounds on the paper. There's a range I use occasionally that has programmable turning targets. I set it so the target starts on edge, then faces me, then turns back after 2 seconds. I prefer the visual stimulus of the turning target to the beep of a timer. I do this drill both one-handed and two-handed. I shorten the time as I improve. So far, my best time is 1.8 seconds, but I can consistently get decent hits on target within 2 seconds (I'm definitely NOT an expert). I use my 642-1, carried in my usual manner (IWB under an untucked shirt). While I normally shoot standard pressure ammo for practice, I do this drill with +P ammo since that's what I carry.

While quickness is a good skill to develop, don't sacrifice accuracy/precision for speed. Don't try to go fast until you've got the mechanics of the draw down. As the old saying goes, "Slow is smooth, smooth is fast."