In addition to what Joseph said, No, it is not good style. If you want paragraphs without leading indentation, use the parskip package.
You are better off in LaTeX marking up what things mean and letting the engine decide how they ought to look. So, in general, when you are tempted to stick in some fine-grained layout command, you ought have a second thought. While thinking, see if there is a package that will provide the layout you are after globally. (In the case at hand, once you've sprinkled
\newline across your document, it will be more difficult to change the appearance than it would be to comment out the