Sorry Jane this is goin to occupy your space; hope it is not is vain
Yoga is often misunderstood as a way to develop fitness but that would mean you are missing the whole picture.
ofcourse it is a way to develop fitness
however
yoga means union of God and soul; nirvana as you would say
so yoga is a way to nirvana
forgive my philosphy....lol
yoga goes in the foll manner
bodily cleansing- purging of toxins from the body
physical exercises-what you would generally witness in a yoga class
pranayama(life force)-all breathing exercises
meditation
there is much more to yoga then you can imagine
these are meant to bring complete harmony in the body and mind typically like the yin and yang
NO ONE IS JUST BORN TO DO YOGA
through regular practice you become flexible
yoga can tone your body and give you desired results
however you need to get a good experienced instructor who know what he is doing
as for tips
go at your own pace, dont force any movement say no to competition
hope that is help full
just note you wont find all the above mentioned elements in a class
concentrate on what you want to achieve
