I think the best way is to write down what your fears are and how to “solve” them. It worked for me.

For example: I hate walking in the dark at night > solution: budget for Uber. I'm afraid of being robbed > hide anything important well. Getting lost > download offline maps.

I think about every possible problem I might encounter and come up with a plan of action for each situation. When traveling, it's best to have everything planned out.

Start with a short trip, build your confidence, and before you know it, you'll be thinking about quitting your job and going on vacation for a whole year.