If your company has some employees (namely, at least one or more salesperson(s) plus one or more marketing personnel), you might be struggling on how to coorindate the efforts of both.
Check out Jill Konrath's free PDF report on What Sales Really Needs from Marketing. (NOTE: even if you're solo, and don't have employees, it's still woth a few minutes to review...to help you market and sell...)
Konrath is the guru on selling to big companies, and some of what she writes is more targeted at larger B2B companies selling to other big companies, but this is definitely worth the quick download and easy read for any small biz B2B'er.