I think I used to know the rules, but once I realized how many energies you need for a working deck, I kind of gave up on that and started collecting them for the pretty pictures. ^_^ Energies aren't cute at all. One time we tried to play with lego pieces for energies, but found the game kind of disappointing. It seems like there's no point in playing without a structured deck, with multiples of pre-evolved Pokemon, something I never had (pretty pictures being my top priority).
I'm still looking for a particular Umbreon card, if anyone is looking to sell! It's the one from Neo Discovery, with a purple temple in the background.