There are a few tips I hear most often about:
#1 In group chats, don’t spam people with endless videos, photos and long passages, or it lessens the members’ engagement in the group. I have heard a case where someone sent 8 variations of a video!
#2 Respect people’s time. Just because it is easy and free to message, doesn’t mean it is ok to message people at odd hours and start a long conversation (unless perhaps if you just met and have a crush on one another, that’s a special case). If detailed chats are needed, usually it’s better to fix a time to call or meet up.
#3 Keep message brief and to the point but not filled with abbreviations. If long passage is required, write an email and jot down some short key points in the message to let the reader know what to expect in the email if the situation fits. The recipient may not understand the abbreviations the way you do so to help them understand your message fast and respond easily, keep to writing in full, unless the abbreviation is very common.
#4 Don’t over use emoticons. Emoticons do not appear the same across devices and people may perceive the same emoticon differently too, better to explain in words and use the most straightforward emotions like a happy face to add some fun to the message without causing any misunderstanding 🙂
#5 Use appropriate profile pictures. Most people use the same account for both personal and professional use. So better to keep profile pictures appropriate and keep wild looks pics in the private collection folder. It may seem obvious, but people do get surprised by their colleague’s profile pics from time to time and judge them differently at work.