A binder clip isn't the only trick: this paper-clip loop keeps tees looking sharp without a tailor.
Paper-clip sleeve cinch that looks like styling, not damage
Oversized tees are supposed to drape, but the sleeves can go full sail the second you step into a crosswalk breeze or raise your arm to tap your MetroCard. When I want that clean street-style silhouette (boxy body, controlled sleeve), I do a tiny cinch inside the sleeve hem with a plain paper clip. Not a safety pin. Not a binder clip hem thing. A paper clip, because it lays flat and it won't poke you when you're carrying a tote.
Here is the move: take the sleeve hem from the inside and pinch a 1-inch fold right at the underarm seam. You want it hidden when your arm is down. Slide the paper clip over that fold like you're clipping a stack of receipts, then rotate the clip so the long side runs parallel to the hem. That rotation matters. If you leave it vertical, it prints through and you can see the little metal bump in photos.
I started doing this with those heavy Uniqlo U tees and a couple of thrifted blanks that had great bodies but weird sleeves. It gives you a slightly tighter sleeve opening, and it also changes how the shoulder sits. The tee stops looking like it borrowed someone else's arms.
If you're worried about the clip flashing, pick a matte black clip (office supply aisles have them) and use it on a black or dark tee. On white tees, I tuck the clipped fold one more time so the metal is buried in fabric. It holds through coffee runs, leaning on railings, and the quick mirror checks you do when you're walking past a storefront. When I get home, I unclip it and the tee is still a tee. No holes, no permanent crease, no weird pin scar.
The tiny hoop trick for a tucked tee that won't balloon back out
Some days you want the tee tucked, but not the full-stuffed, waistband-bulge look. The other problem is the opposite: you do a neat half-tuck, walk three blocks, and the tee balloons back out like it's trying to return to its natural habitat. I fix both with a tiny hair elastic and a small hoop earring (the kind that's 12-20 mm, not a big statement ring). It's a little street-style engineering, and it looks like a deliberate styling detail if it shows for half a second.
Grab a small pinch of tee fabric from the inside hem, about two fingers wide, and twist it once so it forms a short tail. Wrap a hair elastic around that tail 2 to 3 times until it becomes a tight little knob. Now clip your hoop earring through that elastic loop, not through the fabric. You're creating an anchor point that won't tear your tee. The hoop becomes a smooth, rounded "button" you can hook around a belt loop, a waistband button, or even the top edge of bike shorts.
When I do this with high-waisted jeans and a chunky sneaker, it keeps the front clean and slightly cropped without needing a bodysuit. The fabric doesn't slide because the elastic is gripping itself, and the hoop gives you a hard point that doesn't collapse. On days I'm wearing a belt, I hook the hoop around the belt under the buckle and let the tee drape over it. It reads like that effortless street-style tuck you see on people who somehow never have a shirt migrating north or south.
Two small notes from doing this in real life: (1) pick a hoop with a secure closure. The cheap hinge hoops can pop open when you sit down hard or swing a bag onto your hip. (2) don't over-twist the tail. If you twist it into a rope, you'll see a weird spiral ridge on thin tees. A single twist is enough. When you get home, unwrap it and your tee relaxes back to normal, which is the whole point.
Sneaker-lace "belt loop" for those pants with no place to clip anything
Ever try to do a crisp front tuck with pants that have no belt loops, no button, and barely a waistband? Think nylon track pants, parachute cargos with a drawcord, or those slinky wide-legs that look great until your top keeps creeping out. When there's nothing to hook to, I make a temporary "belt loop" out of a spare sneaker lace (or any flat lace) and park it under the waistband. It's the kind of low-key rigging you can do on a bench outside a cafe, then forget about for the rest of the day.
Take a flat lace and tie it into a small loop, about the size of a key ring. Slide that loop inside your waistband at the center front, then cinch your drawstring or waistband back down so the loop is trapped and only a little arc peeks out. You're not tying it around your body, you're just pinning it in place with the waistband tension. Now you have a loop you can hook your tee to using the hoop-and-elastic trick, or even just by feeding a tiny fold of fabric through and tucking it back on itself.
Why a sneaker lace and not a ribbon? Flat laces have grip. They don't slide like satin, and they don't create a sharp pressure point the way a thin cord can. When I'm wearing a cropped jacket and want that clean street-style line between top and pants, this keeps the front from puffing without turning the whole outfit into a wrestling match every time I sit down.
Do a quick comfort check: sit, stand, and take two deep breaths. If you feel the loop digging, your waistband is too tight or your loop is too thick. Swap to a thinner lace. Also, keep the loop small. A big loop can flip outward and become a weird little tail. Done right, it disappears, but it changes how the outfit moves. You stop fussing with your hem at every crosswalk, which is the whole win.