To Buy: 
Buy from the supermarket or health food shop. Check the use-by date. Select one with acidophilis and avoid any with artificial sweeteners, colouring and added flavour.  
To Store: 
Store in the fridge in the container for 2-3 weeks. 
Tips & Tricks: 
To prevent yoghurt from separating when heated, stir it through the dish at the last minute or stabilise it first. To stabilise yoghurt, heat it in a pan with 1 egg white and 1 teaspoon of sea salt. Stir uncovered (in one direction only) for 10 minutes. 
Source: Stephanie Alexander: The Cook's Companion.   
Cooking Tips: 
There are hundreds of uses for yoghurt - as an accompaniment to spicy dishes, in breakfast cereals, to marinate meat, in dips, puddings and cakes. Try to substitute yoghurt for cream where possible.