Niyama, the second limb of Hatha Yoga, is a practice of observances.
Saucha is the first observance in niyama.
Santhosha means contentment. The practice of santhosha helps the individual to gain supreme happiness.
Tapas is a practice to reduce the impurities and to reach samadhi.
Tapas of the words or speech is to follow the art of speaking where you are using kind and gentle words and not hurting others.
Swaadhyaya is the fourth observance in niyama. It includes spiritual discourse, reading and thinking.
Ishwara Pranidhana is the fifth observance in niyama. It means devotion, surrender, constant remembrance.