Write a letter to yourself and write every reason down why you shouldn't be able to accomplish what you want. Let out that inner negative voice and don't censor yourself.
Then draw this monster that says all these things to you. What does he look like. Let him take shape on your paper. If you want to learn more about your monster you can ask him the following questions:
1) Where does he live?
2) What are things that he does?
3) What does he say often?
4) Why does he do and say all those things?
5) What is the thing your monster desires the most?
Now write another letter, but this time write a positive one. Counter all the things your monster said to you and thing of reasons why you will archive that goal! Praise yourself into the heavens. Make it huge! For the best results you use I in this letter instead of you. It feels more powerful this way.
Then once again draw the aspect of yourself that says all these wonderful things about you. Keep this image close to mind and come back to it for advise in future times when you need it.Ask him the same questions that you asked your monster.
In a last step you can transform your monster. Dress him up for a party because your monster also can be afraid and insecure. Make him in a 3D setting or in whatever way you choose and give him a groovy outfit or other adjustments. When I did this myself, I felt closer to my monster afterwards and therefore I felt closer with that part of myself. It felt less frighting. To give you an idea, I will include some pictures of my transformed monster.
I hope this might be helpful to you. I find it such a powerful exercise that I just had to share it. And one last tip: This process can be overwhelming, so you might want to do it together with another person or in a small group of people you trust.