Excellent advice already given I think I will throw my vine whip into action here!
Yeah, it's how you feel for ABDL. Some people play with baby toys or toys meant for kids.
Some wear baby diapers to feel little and the smell regresses you.
Some suckle on binkies while snuggled with blanket.
It's all how you want to approach this, there are many ways of feeling more than just a little. It's not about the diapers (Maybe :3) or about the babyish cloths but all about how you want to feel, it's who you are and how you feel you want to be. Your you right? Do you feel little? Your technically an AB anyway!
While you want to feel more as an AB/DL, it might not snap right away, it'll take time and you have to have patience for that. Some of those I mentioned may easily speed the process up. I do hope you accomplish what you want to be.