Same thing as piano, really. Watch some videos of people teaching proper technique (hand positioning, chord transitions, and then to more advanced stuff when you get ready). A lazy technique will limit you and it becomes a hard habit to break (I know, I taught myself to play when I was 13. Then I retaught myself when I was 19, with the help of some friends of mine who were actually properly tutored).
The big difference at the beginning is going to be the discomfort. It'll be frustrating at first, because the strings resist more than you think they would. It'll probably hurt until you build your callouses, and you'll be really fumbly in general. Keep at it.
When you get all that down, then start playing songs you like. Play it on your computer and see if you can keep up with it. Start simple, of course.
And fiddle around. When you're just sitting around idly (watching TV or whatever), have the instrument in hand and just...make noise. Get familiar with it. Learn the feel of it: How far you need to go to get to the sweet spot in each fret, what going from this note to that note sounds like, what happens when you play these two strings together. That sort of thing. And apologize to your roommates (if you have any), because it will annoy the piss out of them. Just remind them that it could be worse. You could be trying to learn how to play the harmonica...
Also, learn how to maintain your guitar. I don't like to use stands. I could knock it over by accident. It gets dusty out in the open. Sitting at an mostly vertical angle for prolonged periods of time isn't good for it. I keep mine in their cases and flat on the ground. Get used to changing strings, tuning, making adjustments (to the bridge, the pickups, whatever). I play a Fender Jazzmaster mainly, which is a wonderful sounding guitar that is a plays like a dream. But it also requires a good bit more TLC than the average guitar. Learn how to make truss rod adjustments too. You likely won't need it for a long time, but it's good to be self-sufficient. Saves you trips to the instrument shop, and thereby saves you time and money.