Most fabric-based tutorials seem to be based on ruffles... what a perfect idea! Ruffle trees are quick, easy, and can be made with scraps you have lying around. Also, they're ruffles... so they are awesome. Here are two similar but slightly different ideas:
This one uses ribbon and chair railing (which is optional, for flat, un-topped tree). Check it out here.
And one that uses fabrics and odds and ends as bases here.