My job offer negotiation skills are strong (I think)...so why didn't I get anything I asked for?: Easy guide for students and recent grads to evaluate and negotiate the details of a job offer!

You successfully answered the questions in a phone interview, a live interview (or several) and the company just called to make you a job offer! Now what? Getting an offer is exciting - so how do you know if it's a 'good' offer? What are the important parts of an offer to understand? Are there some parts that can be negotiated, and how do you have those conversations? Can you reject an offer, and how do you do that professionally? What about other companies you have been interviewing with -...