Quite often artists don't want to work with you unless they know who else is on the team. The same goes for when approaching agencies. Send out a proposed team list and mention that this is the model or the make-up artist you are looking to work with, but they are yet to confirm. That way you are sparking interest and putting a creative team together. If someone won't agree to work with you make sure to inform the rest of the team.
Also don't be afraid to reach out for advice. There is no clear way to becoming a photographer and its best to talk to those that are already in this profession. If you are having a block in your head cause you don't want to be rejected or this is something you haven't ever done before then that's absolutely normal. From my experience, turns out in most cases people are helpful and willing to share information with you.
First genuinely compliment them about their work. And make sure to be specific about what you'd like to know about and thank them for their time.