Hi Mimiron and Jono,
I agree breathing is really the key to it. You can start each yoga session with pranayama exercises, and finish in deep Savasana relaxation or in meditation.
Variations of some asanas can help you to find one that feels most viable to your own body. With some postures, exercising for example a couple of different ways of entering it makes you more confident and relaxed once you're there even when you enter it the difficult way.
Try vegetarian/Ayurvedic cooking, and consume 1-2 teaspoons of turmeric a day (also, soaked fenugreek for ladies).
In wintertime, drink Vatta-balancing aurvedic herb-tea blends. Gradually minimize or avoid toxins (coffee, alcohol, drugs, additives, meat etc.), white sugar, white wheat flour. Drink often, and as clean water as possible.
If you're in Western sports too, then:
- add swimming to your training (various strokes)
- in a yoga class, don't watch the others. No matter if the person next to you is an expert or an absolute beginner. Let your your inner go-getter or competition freak hibernate as soon as you're on the mat; go for awareness, patience, enjoyment. This is almost as key as the breathing.
Last but not least - practise, and all will come ;-)
Enjoy !