Buy whole flaxseeds and keep them in the freezer, only taking out what you need at the time. Once flaxseeds are ground, their precious essential fatty acids are exposed to oxygen and begin to degrade rapidly. For this reason you should not buy ground flaxseed meal, which is likely to be rancid or at least to have lost its health benefits.
Grind your flaxseeds in a small coffee grinder and immediately add to your food (like putting them on a salad or in granola).
Or if you have a Vita Mix, which I highly recommend, grind your flaxseeds first until they are powdered before adding all those wonderful raw fruits and veggies to make yourself a fabulous green smoothie.