[Update: These ideas apply to Web pages as well.]
A few suggestions from a mere user:
-Stop using script-based popup menus. Go back to old-style Microsoft-standard (c. 2003) clickable nested menus emanating from a static menu bar, with standard headings (FILE, EDIT, etc.) plus the unique headings needed for each piece of software. If you are using script menus as a workaround for complexity you should redesign your user interface. If you are using script menus for any other reason you should stop.
-Knock it off with the icons. Use text buttons instead. The point of software it to economize on human effort, not to appear stylish. A trash-can icon is probably OK, but much more than that and users are forced to waste time mouse-hovering over your icons or (worse) looking things up in the online help.
-Hire focus groups of 75-85 year-old occasional computer users and turn them loose on your products. They may not understand the fine points but they will tell you quickly if your products have any gross UI deficiencies that people like you who use software all day may be overlooking.