To keep uniqueness, you need something that makes people see that your restaurant is special and then, make emphasis on that. That is called "USP" (unique selling point), and if you don't have one, you should definitely start working something out.
There are 3 steps to develop and make correct use of a USP:
1. Establish the structure of the USP
For that, you will think about what is that unique product, service or concept that your business has and why is it different from the rest. When you have got those answers, write it down into three short lines to make it 100% clear. Make sure no one else came up with that idea already!
2. Make your restaurant "dance" around your USP
For example, the USP of a restaurant called "burgers and beers" is about burgers with the best-quality meat from Argentina and homemade beers. The restaurant-design is all about homemade beers and meat in the walls, pictures and graphics. The menu has around 15 different burgers and 10 homemade beers, and they post content about different kinds of burgers and live videos about how they produce their beer.
That is an example of a restaurant "dancing around their USP". When you manage to build up your restaurant around your USP, and it starts looking awesome and unique, you are ready for the third step.
3. Make sure the customers don't forget it
Nowadays, there are many tools to boost your restaurant's unique products or services, but the classic ones are always posting on social media platforms, blogging and making small (or big) events in your restaurant, of course about your USP or connected topics.
This is a process secure and used already for many successful restaurants, and I hope it helps yours as well!