I try to do it in "stretches" when I'm driving around town and the traffic isn't too heavy (I often drive home at odd hours, when there is little or no traffic, and I can maintain a speed of 35 to 45, give or take).
Sometimes, I'll drive with the intention to "charge" until it gets to 6 bars (highest blue).
My ultimate goal is to drive for as long as possible with the instant MPG reading > 50 MPG. I try to do this, regardless of whether she's charging or going on electricity only.
Traffic and traffic lights permitting, I may be able to "drive-and-charge" for 2, 3, or 4 miles, with the occasional slowdown or stop. At some point (while charging), it will either go to 7 bars (green) or not. Either way, sooner or later, she'll really resist further charging, and will actually change her mind (just like a lady) and want to discharge. This is easy to tell, because it'll go from engine + charging to either ICE and Electric or Electric only.
At this point, the computer's "bias" has changed from "want to charge" to "want to discharge," so I'll take advantage of it, and drive in stealth for as long as traffic and the computer will let me. Might as well use it up, as far as she'll let me (usually down to 5 bars <one above half> or 4 bars <half>, depending on my speed, grade, wind, and her effort.
I might only get a half-mile in stealth, or I might get a mile, or maybe longer, depending on grade and wind. Eventually, she'll change her bias back to "want to charge," so I will adjust my foot again for charging, and try to keep geting > 50mpg on the instant display.
So my driving goes sort of like this: Charge until she resists. Stealth until she resists. Charge until she resists. Stealth until she resists. Repeat. Slow down or stop for traffic as necessary. Speed up gradually, but try to do it "with charging," because I'm using gas anyway to accellerate...might as well put the HSD to full use and charge her up for another leg in stealth mode.
It's still fun, and actually, I hardly think about doing all the above. It's just natural now, and I do it without a second thought, and with hardly any glancing at the MFD.