Having reached Town Hall level 7 a couple of weeks ago (yeah, I know, I'm slow), I now have a third resource to deal with: Dark Elixir. The higher-level folks in my clan warned me about how slow it is to collect, but I'm not sure that prepared me for the lack of Dark Elixir I'd find. I had grand designs on getting my Barbarian King in the first few days but I'm barely 2/3 of the way to my first 10,000 Dark Elixir! And now that I've gotten a reasonable amount of it, I'm getting raid more often as well.
One thing I have found is it is really helpful to use the battle log to find suitable amounts of it. Not only is it free to search there, you can lie in wait for anyone on your list to collect a bit more of it (as long as they aren't raided in the meantime). But the real gold mine (no pun intended) are those super-advanced level 9 Town Halls that are dropping trophies. They are the ones putting a single level 6 Archer or Barbarian down and then immediately surrendering. Prior to TH7 I would simply ignore those bases because I would generally be wasting more resources than I could collect. But now, I generally find these bases to have the most Dark Elixir at all, and I can wait until I have as many Lightning Spells as I can store up to attack with. Best of all, they can't attack back!