Well first of all the premise is faulty. Asking yourself how not to focus on your ex and move on is asking the wrong question. It automatically frames everything on the basis of what won't remind you of him and therefore keeps him in the forefront of your mind. It's not conducive to being able to move on, and forget. Also Idk why you're still friends but apparently your thinking about him a lot is a problem so I have to say regardless of how you feel about it, being in contact with him will also keep him in the forefront of you mind.

So my suggestion is to shift your thinking to what you stated already and that is to focus on finding yourself, your path and become independent. Instead of asking how not to focus on things that will remind you of what you had, ask yourself what it is you can focus on now that you're single and what would you really like to do for YOU? Frame all your activities on what you'd like to do, be and strive for and your brain has a funny way of making things happen. It is your slave in the sense that if you ask it the right questions it's sole job is to answer them.

hope that makes sense