Here's the tutorial for making your own sweetheart shrug. This project is very similar to Butterfly Shrug (tutorial here), so I have just highlighted the differences from there. I highly recommend reading the butterfly shrug tutorial first and then coming back to this to better understand it.
For a quick comparison, here's what butterfly shrug front looked like.
Notice that the width is less than the back, neck is higher and it ends with a small straight line, whereas the sweetheart shrug ends with a point.
Now turn it outside and top-stitch. You will have raw end of the strip showing on the outside. This is ok. We'll take care of it later on.
refer tutorial here). I also cut the cuffs of the sleeves slanted instead of straight, I thought it went well with the heart shaped hemline.
You may go with either slanted or straight sleeves.
Cut scallops on the raw edge of the strip at the neck-line. This will help it sit evenly at the neck. Don't worry about making these perfect, they are going to get covered later on.
Sew it along the neckline. Tuck the ends inside. Sew a pretty Ribbon at both ends of neckline. Add some fray check to the raw ends of the ribbon, or keep it over a flame for few seconds to melt the ends. This will keep the ribbon from fraying.
Finish the hems with rolled hem.