[Quiet Man Cometh]

Generally, yeah. Write for clarity, I would say, above anything else. That is, if you are writing for school. If the point of an exercise is to communicate and not impress someone with how well you can work with the language, then you don't really need to worry about long or complicated sentences.

People often use Earnest Hemingway as an example of a writer who does great work with very simple language.