Publication in health sciences journals is the most important tool for the dissemination of scientific knowledge. Particular attention and seriousness are required by researchers so that the articles they submit are of high quality and explicit. Although writing is generally considered to be easy, writing in a comprehensible way can be extremely difficult. This article presents some fundamental principles of scientific writing, aimed at helping researchers to write clearly and to improve the quality of the manuscripts that they submit. Application of these fundamental principles of writing will result in an improvement in the quality of publications in scientific journals and particularly in Greek journals where the problem of clarity is greater.