You doing the academic book thing? Dope! A thread.
1. Do your homework. Sometimes the most prestigious academic press that (more) established scholars fawn over ain't meant for your research. Peep their acquisition editors, their titles, etc. Is it a fit?

2. Don't cold-submit a manuscript. Reach out to an editor. Talk about your work. Tell them where you are in the project. If y'all vibe, they'll ask to see what you got. Have it ready. Which leads to my next suggestions:

3. Don't waste your time or the editor/press' time. Bring your A game. If you are revising your diss, you need to scrap it to its bare bones starring YOU. You the authority. All that citing needs to fall back to the footnotes LOL. How are you changing/adding to the convo?

4. If you are starting from scratch - I did with Chronicling Stankonia - take some to figure out your burning question and its potential answer and learn to elevator pitch it. What you talking about? Why is it relevant? What new ground you breaking or revisiting?

5. Aight so boom you get invited to submit a proposal for peer review. Aaaaye! Your proposal is the blueprint: What's your project about? Why should it be published? Who would you be next to on the shelf? What makes you shine? Why xyz press? What is your timeline?