This post is where James Clear (Idea #2 in this post) and Braveheart meet.
James Clear said it exceptionally well (as he always does), but I would add two things to his advice.
1.) Recognize that the more nervous you are about the request, the more likely you will pick up on negative signals that may not be there.
2.) Rather than ask later, ask differently. Immediately responding to a “no” with “No, or not right now?” is a powerful response.