Traditional smoking or barbecuing is the best substitute for liquid smoke in a recipe. Spicy barbecue ingredients can also lend the recipe a similar flavor.
Liquid smoke is meant to mimic the flavor that comes from smoking or barbecuing meat. Therefore, using a smoker or a barbecue is the best way to get that flavor without liquid smoke. However, if smoking or barbecuing takes too long, traditional barbecue ingredients such as Worcestershire sauce, paprika or other similar spices give the food a smoky flavor. As long as the substitute ingredient makes the food taste like it was barbecued, it is a good substitute for liquid smoke.