This question is asking for a personal response, so I can't tailor it exactly to your situation. Without seeing a baseline writing sample, I can only offer broad, general suggestions on how to improve communication with those groups of people. It also appears that this question is specifically asking about email communication.
One of the first things to remember is that your professors, employers, and business professionals are not your video gaming buddies. They are your elders, your mentors, your bosses, your professional contacts, etc. Consequently, your email communication with them needs to be formal.
One tip regarding a formal email is to remember to put something in the subject line. Keep it brief, and keep it concrete. The subject line of the email needs to make it clear in a few words what your email is going to deal with. An email with a blank subject line shows laziness or...
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