Research Hatshepsut's life. Basic information on Hatshepsut and on ancient Egyptian culture in general is available from many Egyptology websites; more in- depth information should be available at your local library. Joyce Tyldesley's book "Hatshepsut: The Female Pharaoh" reconstructs Hatshepsut's life from the information available in the archaeological record. Tyldesley's book "The Private Lives of the Pharoahs" reconstructs what life would have been like in the Egyptian court.
List key players in Hatshepsut's life, such as her father, Tuthmose II, and her half-brother, Tuthmose III. Imagine how Hatshepsut would have felt about each of these people. Are they villains or heroes? Did Hatshepsut behave kindly towards them, or not? Make this list as detailed as you can--these figures will eventually become the major and minor players in your adventure story.
Select one or two events in Hatshepsut's life of particular interest to you. These might be politically important--such as Hatshepsut's accession to the throne or her removal from powe--or they might be more ordinary. The most important thing is that they inspire your imagination. Begin thinking about the aspects of those events that history didn't record. What might Hatshepsut have felt about what was happening? What kind of covert deals might have been made behind closed doors? Fill in the gaps and your story will begin to take shape.
Research adventure stories. They're not all the same, but they have certain elements in common. A few basic templates are available online. Books such as Michael Newton's "How to Write Action Adventure Novels" give instructions on writing these stories. ,The more different types of adventure stories you know, the easier writing your own adventure will be.
Choose the basic elements of your story: who are the major players? What is the story's climax? Is there a mystery at the center of the story and if so, how is that mystery revealed? The more you read about adventure novels, the easier it will be to identify these key elements of storytelling.
Choose the basic structure of your story. How will its key events unfold? Will the story take the form of a secret memoir written by Hatshepsut at the end of her life? Of letters written between courtiers at the Pharaoh's palace? Or will a third person narrator tell the reader everything he needs to know?
Compose your thoughts on the key events of your story and on its structure into a series of organized notes that you can refer to while your write. These notes will be your road map, helping you push forward at times when you feel lost.
Begin writing. Write every day for as long as you can stand. Don't look back at what you've written until your story is complete. If you suddenly have an idea that deviates from your notes, follow that idea. Some of the best writing comes in bursts of inspiration.
When your first draft of the story is complete, put it away in a drawer and don't look at it for a week. This way, you will be able to edit your draft with fresh eyes.
Re-read your draft. Ask yourself: if I had not written this story, what questions would I have? Would I feel the writer gave me enough information about Hatshepsut's personality? About life in Ancient Egypt? Make a comprehensive list of these questions. They will serve as your initial guide as you begin to rewrite your story.