I fixed up my mantle a couple of weeks ago, but I'm just now getting around to sharing it with you. It's simple and fun.
I use things from previous year, like the black feather wreath (which I LOVE! - got that at Kirkland's a couple of years ago), the skull (probably a Wal-Mart find), and the vase with black sticks. Every year I grab a few scraggly branches from our crape myrtles and give them a quick, black spray paint.
Easy, right? The black candles used to be white and I sprayed them too. I just use them again each year with those old candlesticks. The little white pumpkins came from the dollar store and Wal-Mart, and I painted them white with some leftover spray paint after taping off the stems. Easy.