A great way of making some extra cash is by simply writing articles and selling them as you can set your own price which makes it more lucrative than any other form or content creation out there where people may not be interested because they already have plenty on their plate with work overloads, careers etcetera but if we're talking about something specific then this could really help!
"The Basics"
"How much you can make"
"Proffesional, Friendly, etc"
"Language skills"
"An example for client"