I avoided brown tops for years, convinced they'd make me look like I was dressed for filing paperwork. What changed was trying on a washed out toffee one in a changing room with terrible lighting, expecting to hate it, and not being able to take it off.
The brown that's easiest to live with isn't the deep chocolate you'd pick first off a rail, it's the muddier, warmer shades in between, caramel, tobacco, a sort of faded coffee. Anything that tips towards orange or rust reads costume rather than clothes unless you've got the skin tone to carry it, and I haven't, so I check that in daylight near a window before I even think about the till. Matte finishes wear better day to day than anything with a sheen, because shiny brown has a tendency to look cheap under indoor light in a way that matte cotton or a brushed jersey never does. I rub the fabric between my fingers before buying, if it feels slightly waxy or stiff it'll crease oddly and sit badly by lunchtime, whereas something with a bit of give moves with you and doesn't bunch at the waist when you sit down.
Once you've got the shade right, brown is far less fussy to dress around than I expected. It sits happily next to denim, obviously, but the combination I didn't see coming was brown with khaki, which somehow looks considered rather than like you got dressed in the dark. Cream and off white soften it, black sharpens it, and gold jewellery does more for a brown top than it ever did for my grey ones, there's something about the warmth of the colour that makes gold look intentional instead of leftover from a wedding. It also does the job plain white used to do under jackets and blazers, without showing every mark by mid afternoon, which white never managed for me, not once, not even on a good day.
If you've got none, start with something simple, a round neck tee or a plain long sleeve top in a mid brown, not the palest beige end and not full on espresso, somewhere you can get away with twice a week without anyone clocking it's the same top.
Worn and washed a good few times, the cotton ones fade just slightly lighter and get softer against the skin, and honestly that version looks better than the one I bought.