Everyone has their favorite thing. Sometimes it's a toy, sometimes it's food. Sometimes, it's not a thing, it's a person. But you can't put a person in a bottle, so we won't be crafting with people today.
You've probably heard of "keeping things close to your heart" before, and that's the main idea around this craft. People have all kind of motor quirks, from biting their nails to playing with the collars of their shirts. Corking a bottle with some of your favorite things gives you something to grasp onto when you're being absent minded, and can even lift your mood.
Keeping everything dime sized means you can fill your bottle with more things. Make sure the opening of the bottle is big enough to push two fingers into. That was the objects inside can be regularly swapped out to match your changing tastes. Some of my favorite stuff bottles have been stamps, animals erasers, charms from broken bracelets, tiny shells, tourist shop gems, shoelaces, decorative rocks, robbons and pretty eggshells.
The heaviest stuff should go at the bottom obviously. While color coordination needs to be a priority if you're making this for decoration purposes, ( I recommend a rope string if you're thinking about wearing it as a necklace. Knotting it around the bottle's neck with a bow is a must! ) but if it's just for comfort, feel free to go as hog wild as you want.