The best succinct advice I have heard is to "know yourself, know your audience". And "trust/credibility is everything". The technical, financial, and logical arguments are best used as supporting devices (throw them in the appendix).
1. Know yourself. Create an elevator pitch of what you want. It needs to be one sentence maximum. Do not create a laundry list of unrelated items. What you want can be somewhat vague e.g., "Artificial Intelligence 3.0". But you need a phrase so that later searches can find all the emails, presentations, documents related to your proposal.
2. Know your audience. Your audience is busy, drowning in minutiae, tired of being cold-called/up-selled/bothered by salesmen. What's in it for them? Are you freeing up their time? Or are you asking for help, to free up your time?
3. Trust/credibility. People make mental short cuts. This also applies to people. If you have a reputation for being earnest and forthright, people are more likely to pay attention. If you don't have such a reputation, find someone who does.