It is generally not easy to co-ordinate a theme wedding. Especially with South Indian Weddings that are known for its vibrant and colorful buzz of guests around the place, pinning it to a theme and asking the guests to show in a certain color of outfit would not really work. But you can always alter the decors, the Groom and Bridal outfits and inform a close circle of family and friends. Once you start putting things together for the wedding, then the rest of the things just fall in place quickly. We have a few theme weddings you can pick up a little inspiration from.
1. Beach Wedding Organizing a beach wedding might not be too tough. A lot of Beach Resorts offer their private beaches these days and also help organizing the wedding, decors etc. Make sure the venue is the right kind of place and that the weather isn't melting faces out there. 
Picture Credits: Shades
2. Color Theme Yellow Yellow is a happy and vibrant color that picks up all the happy tones around the wedding. If not the entire crowd, the bridal party or just the closest of friends or cousins managing to wear the same color would help with the theme. 
Picture Credits: Stories by Joseph Radhik
3. Floral Prints Can Only Mean Hawaiian! Obviously the wedding ceremony would be the best only with traditional attire and a formal way of going through the customs. But the reception however can for sure have fun themes that everyone would end up following. Like an Hawaiian themed party is going to get the crowd groove around the place.
Picture Credits: Studio A
4. Let's Call It Lime'n Blue. Another of Color co-ordinated Theme. The colors in here are exquisitely vibrant and looks like a fun party!
Picture Courtesy: Neeta Shankar Photography
5. Rustic Theme If it's a Barn-Rustic theme, people are going to love the ambience around the place. While you're at it, just put on some old memory pictures, Photo stands, fairy lights (no to forget).
Picture Courtesy: Jackson James Photography
6. Color Theme- Purple and Pink! As good as contrast colors can handle the combo, similar colors can too. As a matter of fact, the couple outfit and wedding decors that go well with the colors, will surely create awesome ambience for the Wedding! 
Picture Courtesy: Coffee Stains
7. Classic Chic Theme With the Groom himself riding one of those with the Bride on it, is such a delight. Dark colored flowers against the decor would make them the level of contrast.
Picture Credits: Shades
8. Vintage Love As precious as one of those vintage vehicles, so is the love that grows with no bounds. Add in an old fashioned decor on the vehicle, make sure if the filters on the camera are on, just in time to capture Vintage Love.
Picture Credits: Shades