A hidden mesh layer, a tiny heel-grip kit, and a snap-up scarf fix the three things that ruin good street photos.
The hidden mesh layer that stops the back-sweat print

I learned this the annoying way: black tee, crossbody strap, sunny sidewalk, and ten minutes later you can see the exact outline of the bag on my back in every candid. Street style looks effortless until you realize the effort is mostly sweat management.
My fix is not switching to a performance shirt (it reads like gym). It's adding a thin mesh tank under the top so the moisture has somewhere to go that isn't directly into your outer layer. I keep a Uniqlo AIRism mesh tank and a matte cotton tank in rotation. Mesh for true heat, cotton for those days when the subway is humid but the street is breezy. The key is the fit: you want it close enough to sit flat under a slouchy tee or an oversized button-down, but not compressive like shapewear. If the mesh bunches at the waist, it prints under high-rise denim and ruins the clean line you were going for.
Two details make this work for a street-style outfit instead of a base-layer situation. First, I size the mesh tank so the straps sit a half-inch inside my bra straps. No peeking at the neckline when I do the quick jacket-off, jacket-on routine at a crosswalk. Second, I pick outer tops with a little structure: a heavy cotton tee, a poplin shirt, or a boxy knit. The mesh layer keeps the fabric from sticking to your shoulder blades, so the drape stays intentional when you're walking, sitting, and standing for photos.
And yes, this also helps with the belt-bag strap. The strap still shows (that's fine), but you don't get that damp shadow that makes the whole look feel tired before you've even hit your second coffee.
New-shoe day: the micro kit I stash to avoid the limp

I don't do the "tough it out" thing anymore, not after I spent an afternoon trying to look cool in new loafers while my gait slowly turned into a cautious shuffle. Street style is basically movement. The second you're thinking about your feet, you stop walking like yourself.
So I keep a tiny shoe kit in the same zip pocket of my bag every time, whether I'm in Sambas, chunky Mary Janes, or a broken-in pair of Birks that decides to rub because it's suddenly 92 degrees. It's boring stuff, but it's the stuff that keeps an outfit wearable:
- Two gel heel grips (the thin kind, not the thick foam). If the heel slips, I stick one inside the shoe, high enough that it catches the back of my heel without folding.
- A couple hydrocolloid blister bandages for when the rub spot is already hot. They don't scream "first aid" the way beige tape does, and they stay put through sweat.
- A single alcohol wipe. Sounds extra until you try to stick a heel grip into a shoe that's dusty from the street. Quick wipe, let it flash dry, then it adheres.
- Mini nail file. Not for nails. For the tiny rough edge inside a shoe that feels like sandpaper and you can't un-feel once you notice it.
The trick is using the kit early. The moment you feel that first "warm" spot on your heel, stop at the curb, pretend you're checking your phone, and fix it. Five minutes later, you're locked into the pain spiral and your fit looks different because your body is bracing against the next step.
Bonus street-style detail: I match socks to the shoe in a deliberate way when I'm gambling on new footwear. A crisp white crew with sneakers is obvious, but a sheer black sock with loafers or a tonal ribbed sock with a lug-sole can hide a heel grip line and keep the outfit looking designed, not rescued.
How I keep a scarf top from sliding all night (one snap)

I've worn the scarf-as-top thing to concerts, rooftop dinners, and that specific kind of summer hang where you know there will be photos. It photographs like a dream. It also tries to escape your body the second you do anything normal like hail a ride, hug someone, or reach for a drink.
Here's the one change that made it wearable for me: a single sew-on snap, placed where the fabric crosses under your arm. Not safety pins. Pins show, they distort the drape, and they have a weird habit of popping open right when someone pulls out a phone for a quick street shot.
I use a tiny black snap from a basic travel sewing kit (mine's from MUJI) and I sew it on while the scarf is on my body, in front of a mirror. That part matters. You want the snap to close at your natural "standing around" posture, not the stiff mannequin posture that makes everything feel too tight later. Mark the spot with a dot of eyeliner or a piece of washi tape, take it off, then do six to eight small stitches through the snap holes. Nothing fancy, just secure. If the scarf fabric is slippery, I sew a small square of scrap cotton on the inside first, then attach the snap to that so it doesn't tear the scarf when you move.
Street-style note: I like this with low-slung cargo pants or straight-leg jeans and a loud shoe (Salomon XT-6, Nike Shox, or a glossy Mary Jane). The snap lets you move like you're not babysitting your outfit. When you're walking, the scarf stays crisp at the neckline and smooth at the waist instead of slowly drooping into a sad bandana situation.
If you don't want to sew, tailor tape works for about 30 minutes and then gives up. The snap lasts for years, and you forget it's there until you realize you're not tugging at your top all night.