Firstly, you need to feel a certain connection to the item in question.
Secondly you need to connect with it on a more spiritual basis by meditating with it and getting the item used to your energy.
Thirdly, the item can be charged with a spell that you repeat on a regular basis while focused on the item. If the item is compatible with the spell's intent there is a chance the item will "remember" the spell. Or more accurately give off the correct frequency behind the spell.
It does not work all the time, but sometimes you get lucky.
That is my only advice when it comes to charging jewelry.