I've always loved the half and half updo. I think it's very romantic and flattering, but also easy to make. It's an elegant hairstyle, without trying too hard to be one.
This step by step tutorial from Martha Stewart Weddings may be helpful.
Step 1: Dry your hair and create loose curls, from the ears down. You can use a large-barrel curling iron. (If your hair can't really hold curls, use some leave-in product for extra hold.)
Step 2: Run your fingers through the curls to loosen and separate them.
Step 3: Spray your roots with hairspray, starting halfway down the part and finishing at the crown.
Step 4: Tease the sprayed hair with a fine-tooth comb, in order to create height and volume.
Step 5: Use a soft brush to smooth the teased hair and then gather the sides into a ponytail.
Step 6: Secure the sides in place, using pins. Shape the curls with your fingers. Use a hairspray to smooth out the whole look and give it extra lasting powers. (Martha Stewart Weddings recommend John Frieda's Frizz-Ease 100% Shine Gloss Mist.)
Image source here.