My friend wants a cake similar to this and I'm not sure how to do it. 
http://media-cache-ec0.pinimg.com/originals/52/50/b3/5250b36b3990ce2ea8dd920910cfd08a.jpg

I'm assuming I would maybe print out the shapes and then cut the fondant accordingly (is that right so far?) but then what? How do I get them to stand and stay straight up? And is there a trick to getting nice fondant edges when cutting random shapes with a razor? Mine always seem to be a bit rough. TIA :-)

AMake them with GP a few days ahead of time to allow them to set up. They probably have a skewer or toothpick "glued" to the back, inserted into the cake to hold them upright. Use a nice sharp Exacto, and gently rub any scraggly areas with some shortening or water as soon as you're done.

AGum paste.

Yes is gum paste similar to fondant? I have never worked with it.

AGummier, stretchier, dries faster and harder.

AOr just get some tylose powder and knead it into some fondant.

Thanks so much! Looks like I have some practicing to do :-)

After much looking around I have come to the conclusion that tylose powder is not available anywhere around me. What a bummer.