Unconscious incompetence: You dont know that you don't know. Perhaps we don't even know the skill exists, or if we do we have no idea what we are doing, where to start
Conscious incompetence: You have learned enough to know that you don't know. Perhaps you have an idea now that you need to learn a lot, but you also have an idea of where to focus.
Conscious competence: you know you need to do and you can do it. You are able to execute some aspects of your new skill
Unconscious competence: You know what you know and you can do it without even thinking. You are an expert. You make few errors
Interestingly, in order to learn something additional in a particular skill, we have to force ourselves down a level or two. For example we may be a unconscious competent driver, but if we want to learn how to be a rally driver we have to go down to conscious competence or even incompetence ini order to add this new skill to your skill set.
References
The Science of Rapid Skill Acquisition: Advanced Methods to Learn, Remember, and Master New Skills, Information, and Abilities - Peter Hollins