First and foremost, watch your daughter for signs that she is ready. Maybe try taking the side off her crib for a night or two to make sure she won't fall out (that is, if it isn't too high).
That's about the same age we let mine move up. The transition was easy for us. Take her with you to pick out a toddler bed, this will get her excited about having a big girl bed. The first night, we told her we had to put it together while she was sleeping, but that it would be ready in the morning. The anticipation sent her right to bed so she could wake up and find her new bed. She climbed up on it while it was still in the dining room.
We have a crib that has a swinging/locking door on the side and we left that open for her and let her pick which bed she wanted to sleep in for the first several nights. She picked her crib; then her bed and switched to her crib in the the night; then finally she spent a whole night in her bed. At that point, we were able to explain that her crib was going to be for her little brother now still two months away (well, he was supposed to be).
When little brother came only 4 1/2 weeks later, she was in her big girl bed and he had his crib. She has never even looked back.
We made a big deal about her big girl bed and she just came along for the ride. Now she picks between her toddler bed and a Tinkerbell sleeping bag with a tent. What fun that is!
Make it fun and the transition should go well.