You can use this simple four step plan to create a behavioral experiment.
Describe the problem you are facing: This entails descriptively writing what problem you are facing. However, go further to include the appropriate behavior you should adopt to fight this problem.
Come up with a healthy alternative thinking to this problem: This means you should think of and write down different alternative thought options to the problem and their positive effects on your behavior.
Formulate an experiment: Here you actually try out the effectiveness of this new healthy thoughts you are training yourself to have, as well as the behavior they should produce in you. Do this by putting yourself in a situation that would test your thinking and actions.
Scrutinize the results: This is where you scrutinize the effects of your healthy thought process and if it has successfully changed your behavior. Be honest with yourself! Repeat as necessary