Here's a form of customization that will not make your work faster or more productive, reduce errors, or improve functionality in any way. Themes are entirely cosmetic. They change the appearance and colors of the title bars, tabs, and other controls.
To change Take Command's theme, select “Theme” in the Options menu. The available themes will appear in a sub-menu. Pick one; Take Command's appearance will change immediately. The “Office 2003” theme is the only one which assigns each tab a different color. Otherwise, there is no functional difference between themes.