Put a few stickers reflecting good prices and nobody will care about any decor... you don't even need a sign on top of your store, they will find you.

There is a joke... One guy is asking his female doctor "Do you know if they make or sell Viagra for women?" and she says: "Yes, in any Jewelry store!" :)

Thank you for reply @gn builders.. But, where to put stickers?? also i want my shops jewelleries to be seen from outside..

Clean up and paint your rusty blue gate. Put up a big shop sign across the top. Replace the plastic stools with something that looks much better.

Adding labels with prices will attract customers. Look at some Tiffany windows: their jewelry has prices, too.

Perhaps a canopy would help with the glare/reflection:

thank you @gn builder for suggestion. there is already hoarding board on the overhead part.

hatetoshop will try it

It looks overloaded, but in the interior, it looks great. I love such kinds of shops. I bought my first Rolex from a similar jewelry shop. Now I am wearing a watch I bought from https://furfurfriend.com/, but I still occasionally wear my Rolex. The best thing about such shops is that you can always find a lot of great men's jewelry. Usually, when I see a retail jewelry shop when I am abroad, I enter it and spend at least an hour searching for something I would like because it is easy to find something good at a reasonable price in such shops.

You cannot over light day light, you can light the inside of the case rather than down from the top, using LED tape light or small spots in the corners. this will help resolve the glare issue. Also depending what kind of overhead lighting you have you can put filters on them to disperse the light pattern. Lastly the mirrored backing in the upper cabinets is causing a lot of the issues with glare as it is reflecting all the light. try a piece of foam board in black behind and just place it in front of the mirror, see if that helps. I think black would be better than mirror anyway as it will let the jewelry stand out.