I'm just going through this with DD. She's nearly 3, but has decided she does NOT want to wear nappies.

I invested in some mattress protectors, you know the ones that go on top of the sheet, so if there is an accident you just pull it off and put another on, don't have to change the whole bed.

For the first week, she wet the bed 2 -3 times a night. Now it's only once, usually around 5 -6 am. I cut down the milk she had at night, but she wasn't really wanting it anyway. I haven't restricted her fluids in any way because I want her to learn to wake up when her bladder is full, not just make it through the night because she didn't need to go, IYKWIM.
So far it has been slow going, but we are getting there.
Goodluck