If it's something like a restaurant, just make a listing for it on sites like OpenStreetMaps or even Google Maps, for visibility. Make sure that the listing is fully fleshed out, including timings, photos, menu, pictures of dishes and ambiance etc - this is a step most restaurants fail to do, and it's something very simple/
I'd say also make a website if you don't have one already, and once again, ensure that it's fully fleshed out with the same details as above. Maybe have an online reservation system. Use keywords for SEO so that your restaurant will come up in searches - maybe worthwhile hiring a proper web dev if you'd don't have experience with this.
Then spread word via word-of-mouth, come up with a referral or coupon system, provide discounted meals for the first month etc. If your menu/service/pricing/location is good, then customers will flock to you on their own and they will do the advertising for you.