Boot it up!
Tanya Patrice recently blogged about making your look a little more professional, and suggested wearing slacks instead of jeans. I'm all for that, but if you really love your jeans, and still want to dress things up, a great pair of boots might be the way to go. I know that if I wear a sweater, dark-rinse jeans, and tennies I look like your standard student, but if I switch out the shoes for a slick pair of boots I'll instantly look more capable and grown-up, and the added height doesn't hurt! (Tanya talked about making sure inseams on her pants are long enough - let's just say that I do not have that problem. At all.)
I love these gorgeous Ann Taylor Loft "Phoebe" boots; the contrast detail on the brown pair is especially nice. They're on sale for only $59.99 US, and still available in the full range of sizes. I have a few other pairs of ATL boots, and can vouch for their quality and comfort. So order a pair and give your casual look the boot! (Sorry, I couldn't resist one little pun... :)