Chose an affirmation from the list ('Life is a gift and I am grateful', for example) and repeat it over and over to yourself. You don't have to say it out loud and there are advantages to repeating it mentally. If thoughts intrude or you forget to repeat it gently return to the affirmaiton and start repeating it again. If you are familiar with meditation you can contemplate the affirmation, or if you know self hypnosis you can go into trance and use it as a hypnotic self-suggestion.

Repeat: 'Every part of me vibrates with energy and wellbeing'

Repeat: 'I am the stuff that stars are made of'

Repeat: 'I am one with life and draw health and strength from nature'

Repeat: 'with each breath I become more centred and present'

Repeat: 'My choice is to feel the good'

Repeat: 'I can always see the funny side of life'

Repeat: 'Now is the time for me to be'

Repeat: 'Life is a gift and I am grateful' 

Repeat: 'I sense an inner strength'

Repeat: 'I am the process of beneficial change'

Repeat: 'In stillness I come to the heart of myself'

Repeat: 'Opportunities and possibilities and'