I would cut the pattern you want out of waxed paper, then use that for a guide to cut the piece of fondant for the top of the cake, I would also use a vinyl mat to transfer so you don't stretch out the pattern.
a lot of people us regular paper and fold and cut pattern
I think the easiest way is to do it with the Wilton ribbon cutter (wavy attachment). I recently bought one and really like it!
Just fold paper and cut out the shape. Open up and use as template on your paste. Try not to stretch your paste while covering. Enjoy!
I was afraid of stretching too, and of not placing it exactly centered. So I just placed a round-ish piece of fondant over the top of mine, smoothed it down a little, and then used a small roller to cut it to the final shape once it was already on. I did mine in big, gentle waves - but I'm sure you could do it in smaller waves too.
Although I must say that I was in a BIG hurry for the cake I did this on (the brown, pink, and white polka dot cake). I might have tried it a different way if I wasn't so rushed, but it worked out okay for me.
Thanks for all of your wonderful suggestions! I cant wait to try them - its certainly less intimidating now!
That's what I love about this place! I was just fixing to ask the same question! Thanks for the tips!
I did the same as SugarFiend...put a roundish piece on first, then free hand cut the wave in. Then just lisfted up the edges to put a little water on to glue it down. Worked really well, but I wasn't looking for it to be totally even. Here is the cake I did it on...