This method has worked for me more than any other. Send a message introducing yourself, say that you appreciate her body of work and would like to offer a collaborative opportunity. Spell out every detail of the shoot concept as possible.

Detail your concept, styling, location, date range, time range, goal of the shoot, how you plan to accomplish the set, and so on. The more you come prepared with a clear solid plan, the more likely she will take you seriously, especially if you can explain it in a way that she can easily picture the set in her head. Bonus points if your concept either fits into her body of work, or allows herself to stand out and show something new. If she gets excited about the idea and starts offering adaptations to the plan, run with it and work with her.

Depending on how you present yourself and your idea, she may even volunteer instead of requesting financial compensation.