Some simple advice that's so simple it's often overlooked:
1. Read the help wanted ad carefully and use it to your advantage. Your resume/cover letter should reflect the things they say they are looking for. You need to be blatant. If the ad says "looking for self-directing office generalist comfortable with role ambiguity," your resume cover letter should say you don't need someone standing over your shoulder to work hard and you don't really care about titles, just about getting whatever job your given finished in a manner suitable for its intended purpose.
2. The resume and cover letter get you the interview. The interview gets you the job. So during the interview, focus on the job and your qualities that enable you to do the job well. Don't talk about outside-the-job stuff lke your preferences in music. Employes really aren't allowed to make decisions about your lifestyle preferences, but if you serve it up in a big rambling discourse on the meaning of life and they find out you like music by people advocating death to capitalists, don't expect to be hired. Stay focused on the job.
3. You may not know how to do every single task they outline. You are, however, INTP, so you can figure just about anything out faster than most people on the planet. Just say so. Stress that you enjoy learning new things, and make it clear one of the things your are most comfortable with is change, that after a certain amount of time passes and you've mastered something, you tend to get less interested in it and would prefer to move on to something more challenging. Not only is this probably true (going by INTPs generally) it's also a good thing to say to get into a place that does offer change. If they want you to open mail and answer phones for the next 30 years, you don't want to work there. If they want you to open mail and answer phones until they're sure you're not an idiot and worth investing in, then they'll move you up into something more useful, meaningful and challenging. (It's not all about them. No matter how badly you need a job, a job you don't like will end up worse than living on the dole a while longer.)
4. Even in the interview, stress the information in the job advertisement and be prepared to offer -- hardest thing of all -- detailed examples of how you have done those things OR related things successfully in the past.
5. As noted, appropriate dress is important. I'd not apply for a pallet-moving job in a pinstripe three-piece with a power tie, but I'd dress in a way that the interviewer would not hesitate to introduce me to the company chairman-of-the-board. Clean, neat, demonstrating an awareness of your appearance.
6. Somewhere on the forum there's a thread about reading faces. Go find it and refresh yourself on its tenets and learn the things OTHER PEOPLE look for when trying to get a read on you. While we don't usually deliberately mask ourselves, we do, as noted, tend to avoid eye contact and hold ourselves in. Above all, learning to use your eyes when you smile is really good, especially when you actually do feel like smiling. Be aware of how you look with your facial expressions. Ask somebody and adapt as necessary. You may feel happy and confident and look like you're ready to punch out a wall. You may feel sad and insecure and look like you're ready to step on your flattened enemy's chest and roar with joy. We bollocks this end of things up and don't realize it for years, so ASK SOMEBODY and ADAPT, since people misreading our emotional state is almost as big a problem for us as us misreading others.
Whew.
That's all from years on being on both sides of the interview table.
The only other advice I can offer the forum generally has to do with attitude. Younger people, especially those closer to recent schooling, sometimes have the wrong paradigm in their head regarding jobs. If you mess it up, you don't get a C grade and move on, you get fired and it becomes something you may need to explain in the next job interview. Even worse, this wrong paradigm sometimes shines through during the job interview. This was especially true in my field, explained thusly: You can get the date wrong on a concert in college journalism writing lab and the teacher will mark off five points. If you do that at my newspaper, and send 600 people to hear a concert in the park the day after it was actually scheduled, you're looking for a new job. Change the paradigm in your head.
(mute cry). 
