Most people in business spend a lot of time communicating in writing. While the inter-office memo and the fax are old hat, you will spend a good few hours a day fighting your inbox. Add to this reports, white papers, proposals and resumes, it's certain you will need to sharpen your word power to succeed.
Social Networking -

We are not all social gadflys, some of us struggle to make small talk. It is a key skill to learn though, it is true what they say, sometimes it is more who you know than what!
Speaking -

Public speaking ranks high amongst the worlds most popular fears. You must overcome it and the best way is to practice. It might feel more comfortable working from the safety of your desk but at some point you are going to have to present. Better to have some experience under your belt before being forced to perform unprepared when it really counts.
Sales -

You might think you do not need to sell but we all sell every day. From even before your first day you will be selling, starting at your interview all the way to asking the boss for a raise. In normal life we sell, persuading your partner that you really need that new purchase, getting out of that parking ticket ... persuasion skills can come in very handy indeed.
Negotiation -

If you can't sell perhaps you can negotiate. A lot of the skills are the same but you will find people who have been in business for a while can drive a hard bargain. If you do not have the skills you will lose out each and every time.