I usually shuddered at the thought of doing a rolled hem on a sheer fabric (which of couse tends to fray). I never seemed to be able to get each fold just right and my edges were always full of puckers and twists. Just the thought of it made me pause when choosing fabric, and yet the princessy feel of all those lovely lightweight and perfectly spring-breeze prints and solids, I just HAD to keep them in my sewing plans.
Fear not!
For doing rolled hems is almost child's play if you have a rolled hem foot for your machine!
As you can see in the picture below, the regular foot is on the machine, and the rolled hem foot is on the right, so you can see what it looks like on it's own. If you don't have one, they're an easy purchase, almost all machines come with one, but they are only about $6.00 at a fabric/craft store if you need a new one.
It can be tricky to get right if you don't know how to use it, and the following pictures have things wrong in them just so you can be aware of what to look out for.
Here you can see the fabric is not inside the roller on the presser foot, and is bunching towards the right side instead.
This is what happens: The hem doesn't roll and even though it is folded over once, you're left with a raw edge that frays.
Below the fabric was pulling too far to the left of the presser foot, and so the fabric bunches and twists instead of rolling and lying flat.
Here is the correct way to use the rolled hem foot. First, you will start by hand rolling the hem, and putting all the fabric underneath the whole presser foot, just as normal. Stich about an inch or so, and then leaving your needle down, you can raise the foot and maneuver the fabric into the the rolling part and then lower it back down and continue stitching. You will want the fabric aligned correctly as in the picture below. Note that the right edge of the fabric is aligned with the left edge of the right side of the foot. And the raw edge of the fabric is aligned with the right side of the opening on the foot. You will want to maintain that all the way around your fabric edge and it will give you the perfect and flat rolled hem you desire.

If you come across a seam, you can simply leave your needle down an inch or so before you get there, raise the foot, unhook the fabric, roll by hand, and sew as if you had a normal presser foot on the machine until you get to an inch beyond the seam, and then leaving your needle down, you can raise the foot, and get the fabric into your roller again to continue sewing with the rolled hem foot. It comes out with the beautiful edge in the picture below.
So don't be scared, get out there and work with sheers! Your edges will be as light and breezy as the fabrics you choose!
By the way, rolled hems can also be done with heavier fabrics, but you'll want to have a bigger rolled hem foot. If you look at the bottom, you'll be able to see how wide the gap in the foot is, which is how big your hem will be. Lighter fabrics use smaller hems, and heavier fabrics need wider hems. You can get varying sizes depending on what type of projects you'll be hemming.