A hot bath combined with bath salts is usually the best way to relax after a stressful day. It may also be a good idea to have an early night so that you feel refreshed the next day. Reading a book can also help, as well as doing something else that you enjoy, such as watching television or, particularly in summer, perhaps go for an evening walk.
If you find that being around friends can make you feel less stressed, then you could call them up and go for a quiet drink, or even invite them round to watch a film or for a chat. Hot drinks such as normal tea or herbal tea can help, as well as scented candles or incense sticks. Exercise can also be a good way of getting rid of stress, such as going for a jog or joining a yoga class.