Since editing photos is mostly about creativity, you can't just do a step by step process to become better in photo editing.
You can get ideas by looking at YouTube tutorials or just the work of professionals. If you find a style you like, try to achieve this style on your own photos. This way you'll figure out what works and doesn't work by trial and error.
After a while, you will develop your own editing style(s). You'll never be done tweaking this style, but you'll certainly become better over time.
If you're also interested in Photoshop however, skills are more important. Again, it's just a matter of practising to become better and to know how to achieve certain things easily. In expanding your knowledge, Google is your best friend. If you have an idea, just search for an approach to achieve that idea. Try that approach and review your work. Did it turn out to be your initial idea or did you change your goal a bit to make it easier for yourself? In the latter case, don't let your creativity be limited by the lack of skills and try to gain the right skills for your idea.