When you like to make a necklace with many layers, it is would be best to use these kind of connectors with one large loop on one side and several loops on the other side, so the layers will stay in their place.

The mix of different metallic colors of chains will create a really nice and interesting look, as you can see right here - a mix of Cooper, Black and Nickel all together.
Hanging charms, single stone here and there, and some Rhinestone stone settings will definitely make your necklace look more spectacular!

Have fun creating!
GITA team.