My boys take their woobies, their little toy Mickey mouse to bed. We make them a small drink and have their star each which plays music on the side of their beds with them.
Also we got character doona covers if I put a generic one on they very much do not like it. Having their favourite characters on their bed gets them all excited to get into bed. We also put a baby gate up on the bedroom door frame one do they cannot wander about. When they first went into beds they took so much with them a handful of cars, stuff teddies and just other bits and pieces now just the two things.
We also bought the character toddler beds which the kids loved ds1 didn't want to give up lightning McQueen bed when I decided to get them singles.