Short answer: give locals a specific reason to come on the specific night you are slow, and put it in front of people who already live within a few miles.
Discount the night, not the food. A permanent 20% off trains people to expect it and shrinks every ticket. A Tuesday-only member deal moves demand into the night you need without touching your weekend margin.
Reach people who live here. Tourist reach is worthless for a Tuesday. The people who can fix a slow weeknight are the ones who live fifteen minutes away and are deciding at 5pm.
Make the offer concrete. "Members get a free appetizer with two entrees on Tuesdays" beats "check out our specials." A specific offer can be decided on in one read.
Own your neighborhood term. "Best Italian in San Marco" is winnable. Being the answer to a neighborhood question sends you people who are already nearby.
Where the plans fit. Independent restaurants generally sit on Professional Services for photos, deals and strong category placement. Established names and small groups, especially anyone running more than one room, go to Corporate for multiple locations and premium homepage placement, and the larger restaurant groups take Enterprise where they want to own the category outright across the 904. See current plan prices.
The compounding part: a member who redeems a Tuesday deal and likes the food is not a discount customer. They are a regular you acquired on your slowest night.