• Be humble. Even if you were the best in school/college, you have no business experience nor contributing to the company's profits for now.(not at the extent of your salary, at least).
• Be grateful. Given the above, someone will probably hold your hand and mentor you, for the first few days/weeks/months. Make sure you appreciate his efforts
• Be willing to learn. When I got my first job, I realized I knew almost nothing. Software engineering(and almost all computer science branches) requires constant reading.
• Learn. You dont just have to want to learn, you have to actually do it :)
• Get along with people. Politeness and basic social rules to the rescue.
• Be productive and deliver. After all, that's why the company is investing in you. To help them make more money.

Hope I helped. Good luck Eija.