Congratulations on breaking the next to last glass ceiling. To break the final one you have two tasks. The first is to unite the party behind your candidacy, especially those who supported Senator Sanders. The second is to prepare for the Trump onslaught. I cannot help with the first but maybe have some useful insights on the second.
The fundamental thing to know when dealing with Donald J. Trump is that he is a bully. He uses insults, threats and intimidation to confront his opponents. But the most important thing to know is that Trump, like almost all bullies, is a coward. The best strategy is to stand up to him and hit back. But this should not be a blow for blow exchange. Nor should you engage in his mud wrestling penchant. An asymmetrical response challenging his courage and exposing his insecurities is more effective..
For example, if during a debate he brings up former President Clinton's sexual foibles, the correct response is "I will not bring up your three marriages in this campaign and if you have a problem with the former president you should have the courage to deal with him directly, mano a mano."
Also, if in the debates he calls you Hillary, call him Donald. If he follows his normal stuck and insists on "Mr. Trump," you agree if he calls you Senator Clinton or Secretary Clinton (not Mrs. Clinton.) If he uses "Crooked Hillary" he should be ignored and dismissed with "Are you so insecure that you can only campaign in insults?"
(On the other hand, surrogates should be prepared with a number on names to use in response as the situation dictates. My favorites are "Don the Con,""Dodger Donald," or Donald MacDonald, the clown.)
When he interrupts as he must, ask him why he does not have the courage to listen to a question or hear a response. Ask him why he is afraid to release his tax returns, or face a trial about the failed Trump University. At every opportunity his failures and bankruptcies should be brought up and his courage questioned.
If he brings up your email issue, answer that you have admitted that was a mistake and ask him why he has never admitted making a mistake. Remind him that he has said he has never had to ask God for forgiveness. Ask him if that is a sign of virtue or of insecurity.
At every opportunity mock his answers and his positions. Laugh at his idiotic ideas. Ask if he has commitments from Paul Ryan and Mitch McConnell to fund the deportation of eleven million undocumented immigrants, including their native born children.
Finally, enjoy the exchanges. Have fun. Americans are optimistic, even now. One of the striking things about the GOP primary debates was how grim and serious all the candidates were. Only Trump seemed to be enjoying himself. You need to walk the line between the seriousness of our challenges while not buying the GOP dystopian view. Happy Warrior is the motif.
Be of Good Cheer. Breaking glass can be fun.