To practice yoga safely and effectively, you should follow some basic guidelines, such as choosing a suitable time and place, wearing comfortable clothes, using a mat or a blanket, warming up before the practice, following a sequence of asanas that suit your level and goal, breathing smoothly and steadily throughout the practice, and relaxing after the practice. You should also avoid any asanas that may cause pain or discomfort, or consult a doctor or a teacher if you have any medical conditions or injuries.