I recommend anyone who wants to get the most out of Seattle to get a physical Orca Card (One Regional Card for All, so called because it works on all modes of public transit in Seattle and the greater Puget Sound area) or its digital analogue. Seattle has a very robust public transit system and you can get most places by a combination of bus and light rail.
If you are not from a major city, I can understand how it can be quite jarring to suddenly be in a very densely populated place with a different code of conduct (I am not from a major city, so I relate). If you are the type to make eye contact with (and especially smile at) people you meet on the street, you may not want to do that here lest it identify you as an out-of-towner, or come off as confrontational. If you're in a larger group, please try not to walk more than two abreast on the sidewalk so others can get by. Also, I've found that the "Seattle Freeze" isn't a real thing. Maybe if you're from a particularly outgoing place it can be hard to become used to, but I find that people are no less friendly than any other place I've been. Some people will be caught off guard if you are friendly to them on the street, but plenty will not be bothered by random chitchatting in public places.
You will also encounter the homeless, perhaps in larger numbers than you have seen in your hometown. Not to be preachy, but live and let live, you know?
Regional Stuff
I've broken up region-based information under these collapsible headings, which you may click on to learn more.
This is the place you are most likely to find yourself in, as this is where the company apartments/bunkmansion is. There's plenty to do in the U District, and you have easy access to a Link station. There is a large Asian segment of students at the nearby University of Washington, and thus a wide assortment of nearby Asian restaurants and stores.
Bars | Most observers will find themselves at some point at Earl's on the Ave., a very fratty sports bar and the closest to the AOI apartments. There are plenty more nearby.
Finn MacCool's An irish pub a little ways down the Ave.
Also called "Chinatown", it is an excellent place to get asian food and groceries.
Uwajimaya is the main supermarket of the ID. It has a great selection of fresh fruit and vegetables, meat (especially fish) and all sorts of other Asian staples.