Does your event have a theme, well in my experience every event has a theme, whether they know it or not. The theme can be anything from a simple color scheme to an elaborate fairytale. Even if you don’t necessarily think that your event has or needs a set theme, you should try and create how you want guests to view your event. The theme sets the tone for the event and helps you plan more strategically for your event.
What is the event about and trying to capture? This is the theme that you as event planners should follow. If you are planning an event for an organization and you want the guests to still see how professional your company is; then one of your themes for the event is to look professional and carry that throughout the event. This would mean no wild looking colors or patterns in the decorations, speaking of decorations, in a more professional setting they would be very minimal. The lighting would be bright and if music was necessary, the music would be soft and universal. You as the planner want to respect the reputation of the organization and cater to the audience who is attending the event.
An event can have multiple themes as long as they fit together tastefully. This means do not try an marry two or three incompatible ideas throughout the event. A good example would be the company party that I attended that thought it would be a good idea to display alcohol and drinking games with a theme of family day at a park. Alcohol and family events do not mix well, and that was made clear when most of the families with children left the company event very early. So, when planning themes make sure that they flow nicely and fit with the environment of the event. Take time to plan accordingly and think how best to convey the look that you are trying to accomplish.