Wear an undershirt. A polo is meant to be worn as a base or single layer close to the body, and an undershirt adds excess bulkiness underneath it, and can peep out of the neckline/collar. If you do wear an undershirt, choose one with a neckline that won’t be visible.
Layer polos upon polos. One polo at a time, please.
Pop the collar. This trend has fortunately receded, but in case you were tempted, don’t. It still reads as douchey. If you need to pop the collar in a short-term circumstance to protect your neck from the sun, feel free.
Choose a shirt with a pocket, unless secured. A pocket on the breast of a polo can add a bit of visual interest, but it rarely if ever gets used, and tends to simply sag and become misshapen, detracting from the shirt’s sharpness. So eschew pockets generally, the exception being ones that have flaps and are secured with a button to stay closed.
Wear a shirt with a large logo. While we typically advise staying away from corporate logos on clothing altogether, a logo on the breast of polos has been one of its signature marks from the very beginning, making them quite typical and more tolerable. If you can find one without a logo, great; otherwise aim for those with logos that are tasteful and minimal in size, rather than large and garish.
Wear a long-sleeved polo. There are such things as long-sleeved polos, and while it may be possible for them to look really good, I’ve never seen ones that do. The polo’s heritage is that of a short-sleeved garment for warm weather and active pursuits; to then extend the sleeves runs contrary to its style DNA and looks funny, much like the ill-advised short-sleeve dress shirt.
Wear an athletic polo for casualwear. Polos designed for sports like golf or tennis are made from synthetic performance materials and cut for ease of movement. They’re great for the course or the courts, but shouldn’t be worn outside of them.
Button at least one of the buttons. Having all the buttons undone looks floppy and sloppy. One is usually good. Having all of them buttoned-up changes the look of the shirt considerably, and is ironically a little more of an “anti-establishment” look, if that’s what you’re going for.
Feel free to tuck or untuck, depending on the occasion. A polo shirt can go either way. Tucking, of course, gives you a more formal look, while untucking is more casual. If your shirt’s longer in the back than the front, then it was definitely designed to be tucked.
Have a core collection of solid, basic colors like blue, black, and white. You can’t go wrong with having a few polos in these classic shades. Polos with stripes or contrasting colors on the sleeve bands/collar aren’t always a bad choice but do read as more casual, trendy, and young.
Expand into brighter and more interesting colors. You ought to have something a little different too, like pinks, purples, reds, and greens.