Black shoes look like the safe buy until you get them home and realise black doesn't mean plain. I've bought three pairs in one year that all claimed to be "classic black" and each one was a slightly different black, which sounds mad until you're stood in a shop trying to match a dress and one pair reads navy under certain lights and another reads brown-black like old coffee. Worth sorting out anyway, because a decent black shoe is the one thing that doesn't argue with anything else you own.
The difference between a good pair and a sad one shows up fast. Real leather, even a thin coat of it, takes a scuff and still looks like a shoe. The bonded stuff that's been sprayed to look like leather cracks at the crease within a season and goes grey at the toe no matter how black it started. Check the sole too, because a glued unit that's basically plastic will wear smooth on a wet pavement in about six weeks, and once that happens there's no cobbler on earth bringing it back. A stitched or decently bonded sole with some actual tread, even a shallow one, means you can get years and a reheel out of it rather than binning them before the first frost. Hardware matters more than people admit, a cheap buckle or zip pull will seize or snap, a good one just keeps working and you stop noticing it, which is the whole point.
Pairing them is the easy part, which is exactly why they're worth getting right. Black shoes sit under trousers without pulling focus, they don't fight a patterned skirt the way a coloured shoe sometimes will, and they let you wear a slightly chaotic top without the whole outfit looking like it's trying too hard. I wear mine with grey, with denim, with a black dress where they just disappear into the look rather than finishing it off like a full stop. That's the job. Quiet, not invisible.
If you've got none in black right now, start with a low block heel or a flat loafer style rather than anything with a thin stiletto heel, because you'll get far more actual wear out of something you can stand in for a full day without changing your mind by three o'clock. Save the delicate heel for later, once you know you're actually reaching for the flat pair constantly, which you will.
Try them on with the socks or tights you'd actually wear, not the shop's thin liner, because that half size makes all the difference by the second wear.