It's easy to be annoying. It's easy to be bitchy. It's not as easy to be snarky. To be snarky, you have to learn to be sarcastic with a hint of condescension with every word. So if you want to start snarking with all your friends, you need to find out how to be snarky in different situations with ease.
State the obvious. The key to being snarky is to point out everyone's flaws and imperfections. If your friend complains that she can't find anything in her closet to wear, suggest snidely that if she stopped eating those donuts she'd be able to fit into her jeans.
Timing is everything. If you want to be snarky, you have to be quick to the punch line. As soon as you see a window to be catty, jump in and give your two cents. The longer you wait, the less effective your attempt will be.
Be overly sensitive. Every day people say dozens of things that can be misconstrued in some way. If you want to be snarky, consider each one a personal attack and fight back. By the end of the day, your friends will all want to know what your problem is.
Throw in a little negativity. A snarky person is one who always sees the black lining in every situation. The world isn't all rainbows and sunshine, and it's your job to point that out to your friends and family members at every turn.