>>4484564Three options potentially:
1. Embrace the reflections as part of the composition. Not always possible of course, but in
>>4484531 for instance the reflected tree/sky add visual interest to the top of frame while being unobtrusive to the main subject. Especially at night where reflections are often going to be light sources themselves rather than just ambient reflections you can potentially utilize them in a creative way. Shooting at night generally will also help with the reflections issue, but again not always possible (and not always a solution)
2. A polarizer. CPL (and LPL I suppose) filters can eliminate reflections and make the storefront windows truly transparent. The drawback is that you might also be eliminating specular highlights or other elements you wanted in your composition. Personally, I don't use a CPL in my mannequin shooting but that's more to do with me (I'm often shooting at night and always on film) than the filters.
3. Wait or change the composition. Not rocket science but if the angle of the sun is causing a streak or reflection then just moving to the side or angling your camera differently can eliminate it or at least remove it from the frame. And if you're set on a specific framing that you don't want to change then waiting for the light to change or coming back another time might be the play since you can't exactly control the sun or other light sources on the street.
Hope this is helpful anon, and if you have some mannekino to post I'd be very happy to see your photos.