|image credit: Sterlic via Flickr|
Get a pot where you can put all your water in it and still have 2/3rds to 3/4ths of room left at the top. You're going to add things to this, remember. When in doubt, use a bigger pot.
Now, here's where this gets a little technical and annoying: don't use hot water from your tap. I know, I know, it seems like it'd take less time to get to boiling if it's already hot when you start, but the thing is, you never want to use water from the tap for consumption or cooking that is hot. It actually carries lead and other built-up gunk from inside your pipes. Instead, run your water on cold for 20-30 seconds, then fill your pot.
Then just turn on your stove, all the way on high -- it's okay, you can turn it down when it's going.
Here's the thing about boiling too: it happens at different temperatures depending on your altitude. Around 212 degrees Fahrenheit at sea level, around 203 degrees up here where I am, at almost 5000 feet. But because no one expects you to use a thermometer, know that a simmer is some little bubbles and slight movement, slow boil is some large bubbles, and a real or "rolling" boil is, well, giant, fast bubbles, "rolling" water, and it keeps bubbling WHILE you stir it.
Learn about how long it takes to boil on your stove, because while a watched pot is a safe one (and yes, it will eventually boil), most people don't hang out right in front of their stove while waiting, and once it's boiling, it'll start to evaporate quick. And if you have cheaper pots that have the coil glued on the bottom and your pot boils dry, you can melt the bonding glue... then you pick up your pot, the hot coils fall off onto your kitchen rug and catches your kitchen on fire, which your husband has to put out while you stand there gaping like an idiot.
Not that I'd know or anything... *cough*