How to Keep Houseplants Alive?

I love having at least one plant in every room. And I usually think a room feels sort of stale if there's nothing alive in the space. But, you guys, I am killing houseplants left and right and I'm spending way too much money replacing the goners!

I know a lot of you have the greenest of green thumbs - so I'd love to ask you - What do you do to keep your houseplants alive? Water from the bottom? How? And how much? Do those glass bulb water things work? I read online once that leaves with brown edges means you're over-watering. Plant-tending is finicky business!