Dr Richard Carlson is thought to be an internationally famous expert on happiness (считается всемирно известным экспертом). Tens of millions of copies of his self-help guides have been sold around the world (руководств по самосовершенствованию были проданы по всему миру). These books try to help people deal with the many difficulties of life so that they can become happy and feel strong inside themselves.
Dr Carlson is a qualified psychologist, also he is naturally optimistic (по природе оптимист) and has always had a deep interest (проявлял глубокий интерес) in the idea of happiness. When he finished his university studies, he began giving lessons on how to be happy to small groups of people. Dr Carlson enjoyed that work but he wanted to try and help more people. He got an opportunity to do this when he began writing articles about happiness for a newspaper. He then had the idea (затем ему пришла в голову идея) of putting his ideas into book form.
One of the secrets of happiness, Dr Carlson believes, is to approach problems in stages (заключается в поэтапному подходе к проблеме), breaking the problem down into parts that can be solved bit by bit. "Problems often seem so large that you feel shocked," Richard Carlson says. "Tt's much better to stop a moment and see things in perspective."
Another advice is to develop a feeling of inner strength. You must consciously (сознательно) try to be positive about things, seeing problems as challenges. When you have a habit of being positive and optimistic, a lot of your porblems either become unimportanit, or else they disappear altogether (в целом).
Dr Carlos also stresses (подчеркивает) that it is very important for people to take responsibility (брать на себя ответственность) for their own happiness. When you realise (понимать / осознавать) this, it can give you a sense of power. Instead of blaming others (вместо того чтобы обвинять) we should learn how we ourselves can change to improve the situation. As a result your personal relations (личные отношения) will improve and you will feel happier (счастливее).
Dr Carlson also recommends people to develop a sense of presence (присутствие). What he means is that we should always be focused (сосредоточены) on whatever it is that we are doing at any particular time (каждый отдельный момент времени). If you are successful at doing this, others will respect you (Если вам это удается, окружающие будут вас уважать). Millions of people have benefited (получили пользу) from Dr Carlson's common sense (здравый подход) approach to happiness. He manages to make complex issues easier to deal with (ему удается упростить решение сложных вопросов).

internationally famous expert - всемирно известный эксперт
self-help guides - руководства по самосовершенствованию
naturally optimistic - природный оптимист
approach - подход
to stress - подчеркивать
consciously - сознательно
responsibility - ответственность
whatever - что бы ни
or else - иначе, в противном случае
realise - понимать
have benefited - получили пользу
common sense - здравый смысл / подход
so what ... подлежащие + сказуемое - для того чтобы ...