Just like we always say, details matter! You have to pay attention to the feedback from your customers. Do they like the specials? Is the price fair? That way you can know how attractive are the deals, and if you need to change them.
Also, play the accountant every time you make the Happiest Happy Hour. What you want to achieve is a balance between the number of sales and the income each sale generates. Always look at the final result, your overall profit. If it’s going up, stick with it! If it’s not, hit the brakes because you’re wasting money.