Be Consistent
Be Clear
Be Courteous
Always assume an image is copyrighted (1).
Internal use qualifies as commercial use (1).
If you use an image, even in an internal presentation, you legally require permission to do so. If you use images published under a Creative Commons license, make sure you follow the terms of the license (i.e. you will often need to "attribute" the image).
I use a lot of images from Jono Hey at Sketchplanations on this site. Mainly because they are excellent but also because it clearly states this on the Sketchplanations website - "If you would like to use a sketchplanation in a blog post or for non-commercial purposes, please go ahead." I have made a contribution via "Buy me a coffee".
Other images... I often use my own images and I try to use other images available under a Creative Commons license. Where I use images from other sources, I always link to the orginal rather than serving a copy of that image. Some images I have found on public sites like Pinterest. I accept that my use of these images is, possibly, a legal grey area. But, I do make sure that the top-level page of this site includes a feedback form where copyright holders can request any item be removed. There are images on this site that were added before I became aware of the legalities involved. It is my aim to either gain explicit permission or remove any images where there may be doubt over permission from my site over time.
However, please note that this site is, primarily, my repository of information for my own use and, as such, I view my use of images to be very similar to if I had bookmarked the image on Pinterest... i.e. they're my bookmarks but anyone can see them. For as long as this site continues to make no meaningful profit I'm comfortable with that position.
Embedded YouTube videos... "YouTube allows users to embed videos from its site by providing the html code to do so." (2). To generalise this point; I believe it's fair to assume that if a website explicitly provides the code to embed their content in your site then you have implied permission to do so.
quod grātīs asseritur, grātīs negātur ("What is asserted gratuitously may be denied gratuitously")
The single biggest problem in communication is the illusion that it has taken place.
Georg Bernard ShawDRIP
Differentiate
Reinforce
Inform
Persuade
AIDA
Awareness
Interest
Desire
Action
State your assumptions
(optional) Present the model you're testing and state your Hypothesis
Lay the groundwork (what you are analyzing, what your variables mean, why you're analyzing this)
Explain your findings for the first part of your analysis (what analyses you've done on the data, why you did it, what your findings were)
Present and explain your second piece of analytics
Summarize your findings
Link your findings
Things to avoid...
Writing too much. You really, truly don’t get paid by the word. People say they understand this point but then write as though they don’t. No one will ever love your details as much as you do, so be discriminating about what you include.
Burying your purpose. Remember when you had to have a clear thesis in the introduction of your school essays? Make sure there is a clear point early in your email as well.
Failure to answer the questions asked. If someone asks you two questions and you answer one, that’s annoying. Good email writers are also good email readers. You can’t skim and expect to get everything. You have to listen to the other person. If you went out on a date and your date said “I love fiction and read at least two novels a week” and you absentmindedly replied “Oh, I hate novels too,” that wouldn’t go over well either.
Excessive familiarity. If you don’t know someone, beginning “Hey Ryan” and getting chatty out of the gate is presumptuous. It’s even worse if you’re writing because you want something from that person and that person is under no obligation to do it.
Failure to respond. In non-urgent situations, I’m not a fan of the whole instant-response email culture. Constantly interrupting brain-intensive tasks to jump on incoming emails does not support thoughtful analysis at work. But if you don’t respond in a timely way to customers and clients and bosses to tell them you’re at least working on their request or inquiry, they won’t know you are out there tackling what they have sent you.
Errors. Don’t listen to people who tell you errors don’t matter as long as people know what you mean. We all make mistakes, but it’s important to minimize them in email. Errors – whether in numbers, words, punctuation, or anything else – dent perceptions of the writer’s professionalism. In addition, errors regularly prevent people from knowing what the writer means. A missing “not” might be a big deal!
Escalating unpleasantness in writing. If things are getting heated, it’s usually better to drop the email and call or arrange a meeting instead. Language began as oral communication, after all – not as email.
https://www.atlassian.com/blog/teamwork/professional-email-etiquette-tips
Don't just say, "Hi", it's like phoning someone and putting them straight on hold. Add some context.
Be clear and intentional.
Don't think out loud, one line at a time.
But also, don't send a single message the length of a book chapter,
Don't forget who you are talking to. Consider your audience.
Write empathetically.
Summarised from: https://www.grammarly.com/blog/work-chat-etiquette/