Understand in advance what your major workflow is going to be, and design your form around simplifying the functionality of the task that your user will spend 90% of his/her time performing.
Mark
And remember that you're designing a business app...i.e. a database...not a video game!
We all like our apps to be nice looking...but as Mark said...it's really about making it as easy as possible to perform the desired tasks! I see so many first timers who haven't begun to learn the basics of database design...not even the number one must...the underlying data design needs...spending days and days and days worrying about having bells and whistles that resemble said video games!