Yoga is a challenging discipline for the beginning to the advanced person. The asanas, or postures are slow and steady and are not meant to be painful, but this does not mean that they are not challenging. Never extend yourself too much to cause discomfort. With practice, you should see yourself relaxing into the stretches with ease.
Nevertheless, for beginners there are a few tips when practicing yoga. Release all thoughts, good or bad before you begin. Turn off your phone and dont answer the door, you need peace and quiet. Make sure you take a warm, relaxing shower and that you wear comfortable clothes that will allow you to stretch easily. You can use aromatherapy that will relax and help to clear you thoughts. You will want to purchase a yoga mat so you can rest on the pad and not slip and slide on the floor. Make sure your shoes and socks are off and that your hair is either comfortable pulled back or no, whatever feels better. Turn the lights low (or you can do it in the sunlight), whatever suits you. You may want to turn some relaxing music of nature, perhaps the beach. Belts or ropes are used to grab your legs and pull them into a better stretch, which should feel delicious. Blocks are used to prop yourself up and sit better or for standing postures.
Without the prop support, you may not be able to attain some postures. Just remember that although the postures are important, performing them absolutely perfectly is not the goal. Yoga is not just an exercise; it includes the mind and intelligence and the reflection in action. These tools make it easier for you as a beginner in yoga, but you will find that eventually you will not need them. Some people prefer taking a yoga class so they are guided properly. There is nothing wrong with this, but keep in mind that only you can take your mind and spirit as far as it was meant to go, alone.