To begin reworking recipes you first need to know what you want to make. Do you want to bake? Make a protein? A salad? All of these are very different when it comes to preparation. Baking is a science, without a firm foundation in baking fundamentals, slight changes can cause havoc!
Once you have a recipe that you like (almost) find what needs to change, do some research on adequate substitutions to make sure you aren’t creating a disaster!
The next step is to test it! I suggest doing this when you don’t have people over or during any kind of event. The best time is when you’re home alone or with your close family to experiment.
Once its done cooking/baking/chilling etc., find what worked and what didn’t and do it again until its perfect!