We did it by putting Katie in her moses basket (which I think is similar to a bassinet) inside the cot for a week or two, so that she could get used to the room before we put her straight into the cot. We also put her lovie (a piece of muslin) into the moses basket for a few weeks before the move, and I slept on her cot sheet for a day or two so that it would smell of me rather than "new".
Oh - the one other thing I did was put rolled up blankets either side of her and accross her head in the cot so that it would not feel so big. She loves snuggling up to the one accross her head and so we still have that one in there now even though we've taken the ones away from the sides
As you can probably tell I was worried that she wouldn't like the move - but it was all fine and she didn't seem to notice any difference! I suspect we didn't need all the precautions but I was worried that the cot would seem really big after her cosy little moses basket...
Bryony