The time has come for your 3-year-old to sleep in her own bed, but she doesn't share your enthusiasm for the idea. She asks for countless glasses of water, keeps tiptoeing down the hall and generally refuses to stay put at bedtime. Establishing a nightly routine and being consistent about not letting her sleep with you are key steps in eliminating the battles and having her sleep in her bed like a big girl.
Enlist help. When your 3-year-old sees that you and your partner are a united front when it comes to staying in bed, she will be less apt to try and divide and conquer. Establishing nightly routines with each of you further cements that once the process starts the only possible end is with her in her own bed for the night. If you don't have a partner, perhaps a family member can call her each night and tell her good night as part of the bedtime routine.
Use a photo chart. Place photos on it of your 3-year-old getting her jammies on, brushing her teeth, reading her bedtime book and climbing under the covers. Include any other nightly routines that are important to you. Seeing the pictures helps her remember the order she is to do them so she comes to expect the routine.
Leave her in the bed. If she cries for you, wait five minutes and then go to her, assure her that you are in the other room, but do not get her out of bed. It is OK to sit next to her bed for a few minutes before leaving. Increase the time you wait to go to her by a few minutes each time. If she gets out of the bed, put her back in it as many times as it takes for her to fall asleep.
Praise her when she sleeps in her bed. Ignore negative behaviors and reward the positive behaviors. When she does sleep in her own bed, praise her in the morning for doing as she was asked. Perhaps make her some special "big girl" pancakes, or go for a morning walk together as a reward for staying in her bed.