1. straight as it is written on the winning letter.
for number 2 im not sure what to say but i recommend u to write as it is but if you are persuing a higher degree or in the process of getting higher degree. you might put down "continuing student" (u could explain to them that u are taking a year off to prepare yourself for tests, toefl, etc..) or simply put down "unemployed".
3.i recommend that the mail to be there safely and on time so I would go for fedex,ups or dhl.
4.Im in engineering myself and i put down "technical", u might use the term "computer related field" since your a Cs major.
by the way, where are u from? are u currently living in the states? do u have high or low case number?