Everybody has an opinion on how a Christmas tree should look (which is as it should be).
I love the tree we've used the last few years because it is so skinny and sparse. I decorate it the same way. It has a few very pretty glass ornaments, some large sparkly snowflakes, finished off with dried orange slices. When I was growing up, and again when my daughter was young, we made new ornaments every year. I think that's why I like to do the oranges now--that and they smell so good!
Here's how I do them (though remember--it's not rocket science--exact time, temperature, and technique are not crucial to their success!):
Cut the oranges into approximately 1/4 inch slices. Remove seeds (they'll look a little prettier--though I forgot this time). Spread out on a cookie sheet. I used parchment paper to make clean up easier. Bake for about 4 hours at 200 - 225 degree oven. Mine were still a little sticky, but they'll finish drying on the tree. Hang on the tree with ornament hangers or just plain wire, and they look like little stain glass windows!