DD got a toddler bed from my Mum for her 2nd birthday. She "helped" Daddy assemble it in her bedroom and then "helped" put the sheets on etc. She then put her teddies to bed as a trial. The cot was still in her room at that stage. That night we asked her if she wanted to sleep in her cot or her bed, she said bed and she has slept in it ever since.

The toddler bed fits a a cot size mattress and is very low to the floor. I don't think she could really tell the difference between her cot and the toddler bed. Sometimes she still calls it her cot. I think having her being involved in setting it up etc really helped the process.