Often forgotten basics for both projects and non-projects environment:

Smile.

Be welcoming.

Introduce yourself.

State your objectives.

Unveil full agenda.

Some soft rules:

Human stories convince. Show human faces. Bring them as guest speakers, if possible. Protect their identity, if necessary.

Present as a believer. I cannot convince, if I am not convinced. It needs to create an emotional connection, that will stay with your partners beyond your interaction.
Give numbers in a context. Otherwise, they are empty shells. They say ” lies, damn lies and statistics” for a reason.

Do not preach; use “we” not “you”. Do what you “preach”. Otherwise, can say good buy to your credibility at a next encounter.

Two-way communication is key. Listen. Create time and space for learning from communication. The result might get you to a total which is more than the sum of the parts.
The efficiency of the receiver depends on the efficiency of the sender. Always. If nothing follows after your email, revisit it.
Have a non-communication expert to communicate. Have yet to meet an outstanding communication expert, both a knowledgeable and mindful practitioner.

Divorce the orthodoxy of power point presentations. Have a different approach: stage a show, use class room presentation materials e.g.

Power point is visual media. Use images and diagrams on a “one per slide” basis. Keep the text for hand outs.

Be humble and honest. Focus on lessons learned and what you plan to do with them.

In development work, aim to embed results in our counterparts’ work through their communication channels. It builds both visibility and ownership.

Enter into communication partnerships and alliances. Design, mold and promote common messages.

Smile. Create a stereotypes-free fun environment.
Always revert to your objectives. Seek confirmation of objectives achieved or delve into what more needs to be done for a happy communication.
You may wish to visit other more academic related sources, e.g. the Open University free courses on Communication or the Harvard Business Review and share your views and experience.