[cranks]

It is incorrect to put a polite お (丁寧語. Sorry I don't know the proper technical term for it in English.) when referring to yourself.

For example:

somebody: お元気ですか？

you: 元気です

This is "technically" correct. However though, you just don't say "お元気ですか" in a conversation, and you never answer to it with "元気です". お元気ですか is something you use in a letter, kind of like "sincerely". You don't answer to "sincerely" like "Oh, I care about you too!" right? That'd be odd. I don't know why all those Japanese teachers like to teach you this expression. It's a direct translation of "How are you?" and sounds weird most of the time. Ask them how many times they've actually used it in conversations in real life. Chances are, they have never used it except in writing.

You'd come across much more natural talking about the weather or the traffic. Avoid saying "お元気ですか？" in a conversation and/or answering "元気です" to it. If you wanna say "how are you?", something like "最近どうですか？", "最近何かありました？" or things along that line sound much better to me.