First, take the tea bags out of the box! A flimsy piece of cardboard won't keep your tea fresh, even if it is lined in wax paper. If the tea bags are in individual packages, leave them in these but still remove the packages from the box. I prefer a tin for storage, but a sealed plastic bag, food storage container or wood tea box works as well. The goal is to protect the tea from moisture and air.
Avoid the Pantry
Don't store tea where you keep spices or other foods. The tea leaves absorb the scents of flavors of these items which can cause your tea to taste off. I keep tea in a narrow cabinet earmarked for tea and beverage mixes, but any cabinet that doesn't contain strong-smelling food items works well.
Keep it Dark
While a glass jar seems like a great airtight, moisture-proof place for storing tea bags and looseleaf tea, the glass allows light in which speeds up the decline of the tea. If you must store the tea in a glass jar, keep the jar in a dark area or place the tea in a dark-colored bag inside the jar to help block out the light.