Taxing and pricing plastic bags proved to be an effective way of reducing their use. We should also apply this in every other material choice the customer has. For example, when asking for ice-cream, cookie cone (edible) or plastic? If you choose plastic, pay an extra.
No spoon, free. If you want a spoon, it's an extra.
Most single use plastics are used and tossed because they are given to the customer free of charge, it's free, and thus nobody values the resources in them or the waste it makes.
In the food court, give the option of real cutlery for a deposit, or buy disposable for a higher price. Same with glass and plastic cup. Charge for the spoon for your yogurt. It's the same than giving a discount to the ones that choose to reject plastic option, but more effective.