I learned this technique only a week ago, from my son who's taking
a yoga class. It's amazing! It seems to work better for me than
any other breathing technique I ever tried. Best of all, it
gets my right nostril to work as efficiently as my left one, which
it doesn't always do (I also tried alternate breathing and gave up
on it because it felt stressful and boring.)

For ujai breathing, you first get a handle on it by breathing through
your mouth the way you would if you were trying to vapor-breathe on a
mirror you want to clean, or on ice-covered glass to thaw a circle
in it. The actual ujai breathing is done through the nose though.
You keep your mouth closed (but not tense), curl your tongue a bit
and touch its tip to the border between your soft and hard palate
(much farther back than the more common deep breathing techniques
where you put it right behind your upper teeth). The trick is to
make a sound that resembles the sound of the ocean, but not through
your nose -- the sound has to be formed deep in your throat!
Visualizing an ocean while doing this in a quiet dark place helps
tremendously. If you're doing it right you don't just get the sound
that "resembles" that of the ocean -- it is EXACTLY THE SAME SOUND!

The moment I "got it" it felt sooo right... I practiced it in
the bath tub last night when I felt I needed some heavy duty
relaxation (a candle, a large quartz crystal for it to shine on,
artemisia/pine needles herbal decoction I added to the bath water,
and the sound of the ocean... and I think I woke up a happier,
healthier person today for the experience... always feel better
when I manage to take "taking care of myself" seriously and do
the whole nine yards...)

Elena