I stumbled upon this informative infographic. Writing a sentence is not only jotting a string of words. According to this check list, there are a bunch of things to reckon with. Maybe we do this unconsciously or automatically but it is still interesting to see how it works.
My own addition to this is: keep your sentence short. Short and simple sentence is easier to understand and it reads fluently.
I hope this infographic is useful for those who want to start writing.