So apparently DotA is surprisingly popular at my residential college (Rice's equivalent of a 'dorm'), and we have players that run from casual dudes to people in clans. I have Warcraft III and stuff, so I decided to join in on the fun.
My roommate has already showed me the basics, like last-hitting and denying. My questions are: 1) what hero(s) should I start out learning the ropes with, and 2) is there anything a new player should know for sure that might not be readily apparent?
There is some discussion in this thread on those very topics a few pages back. Skeleton King is probably the easiest hero to learn, as he only has one active skill.
As for things that new players should know that might not be obvious, one that I would say comes up a lot is staying with your team. It sounds really obvious, but simply showing up to team fights is a lot better than sitting them out. Even in the very worst case scenario, if you show up, you'll still soak up damage for your team. Which is something. And something is better than nothing.
Oh and all heroes have 25% spell reduction. So if you use a spell that does 100 on a hero, it will actually do 75 damage. This is very important for calculating whether or not your or your opponent will survive a given attack.
On a closing note, if you really want to learn, I still recommend the same guide that I took a great deal from.
http://www.playdota.com/guides/comprehensive-gameplay-guide
It's a very, very large index of every single thing you need to know about DotA, but if you have the time it will expand your knowledge immensely.
It's great to have some new Smogon DotA players! Hope we can play some matches some time!