Place your computer monitor directly in front of you if you want to discourage people from interrupting your work.
Dump all the unnecessary papers like past drafts, memos and the likes. Organize all your paperwork for easy accessibility the next time you need it.
Keep important papers or equipment within reach. Your phone, computer, filing cabinet, fax machine and printer should be within reach if you use them frequently.
Tidy your desk space at the end of the day, noting what you need to work on tomorrow.
An L or U-shaped table is a much better choice because of the bigger space it provides. Having small drawers under it is also a good idea to increase storage without taking up too much space.