Clover Taking Over!

I’ve recently noticed a problem in my yard: Clover is taking over!

What started in the groundcover around my palm tree has crept into my flower beds, lawn and more. I keep pulling up the clover, but it seems when one is gone, two take its place.

Does anyone have tips on getting rid of clover?

I’d rather not use chemicals, if possible.

Photo Credit: http://www.flickr.com/photos/jelene/2314601489/