The easy way is to keep a "Barney" magazine on hand. Named after the Andy Griffith Show's Barney Fife, who only was allowed to keep one cartridge, and that in his shirt pocket, the Barney mag is kept loaded with one or two rounds (though you can load it up if you prefer) simply to aid in loading up at the start of the day (or match stage).
When loading up for the day, retrieve your weapon, insert the Barney mag, rack the slide, drop the Barney mag and put it back on the shelf. Insert your normally loaded duty/carry mag and holster.
It's a little less fumbly than the "chamber one, then top off the mag" routine.
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As rcmodel indicates, the simplest (Did someone say lazy? Well, it wasn't ME!) way is to ignore the theoretical capacity and just go with whatever fits in your mag, not bothering to top off. I will admit to this when carrying my xDM. I can't seem to get too awful worked up about the possible detriment of having to reload after 19 shots instead of number 20.