Hello! Here are some things you might want to consider for your restaurant on Instagram:
1. Try to partner with food bloggers. Instagram is probably the best place for promoting restaurants, and there are thousands of food bloggers there. You can try contacting some local food blogger and ask for promo materials in exchange for a dinner or some other benefits.
2. Present new dishes and drinks. Use your Instagram account to keep users interested with new items on the menu. You can even ask your audience for help with naming them.
3. Make your account easy to find. Use hashtags that include the name of your place and some signature dishes or drinks. This will improve your restaurant's search results as more people will be able to see your posts.
4. Talk with your audience. There is room for creativity here. You can run a small contest, poll, ask to share your impressions, publish recipes, and much more.
5. Shoot videos. Instagram Stories and Reels are two powerful tools that allow you reach a lot of people and increase engagment by allowing people quickly react without much effort.
Quite obvious things, but a good way to start. Hope it helps!