Tea is hygroscopic. This means that Tea has the ability to absorb the moisture that is there in the air. In short, moisture is the worst enemy of tea. Hence it is highly crucial that you store the Tea in an airtight, opaque, non plastic container. Avoid keeping it close to a water boiler, refrigerator or a dish washer.
It is important to store it in a dark place away from direct sunlight. Avoid keeping the tea near heat sources such as oven or hob / stove. Heat exposure will ruin a perfect batch of good tea. 
Always remember that once the lid is open and there is a strong odour in that particular area, the tea will absorb it all. Hence the tea that you have bought with love will no longer be in its original form. It is often seen that the tea is stored in plastic containers in shelves in the kitchen above the hob. Remember that the kitchen is a place where 'smell' rules. Every single time you open the lid to take out a spoonful of tea, a certain odour which could be of the garlic fried or dal cooked would be infusing your tea. It is advisable to keep it away from the shelf above the hob / stove.
Please remember, the way you store your tea will define the shelf life of the two leaf and a bud.
* Cover photo credit Poorna Rajpal