Animal studies continue to have a vital role in science development. The aim of this review is to provide to new investigators an overview of the important steps involved in experimental designs and also to suggest some practical information that is commonly associated with this process. Investigators should adhere to the ethical procedure and follow strictly the scientific method. Both the aims and well-formulated hypothesis are essential and practical. In this regard a profound literature search and the aid of an experienced statistician is encouraged. The need of randomization, blinding, and attempting to minimize variation is discussed and recommended. The choosing of good control groups and the employment of pilot studies are useful. Finally, the formulation of new questions to be further responded is expected.