Patent searches can be conducted to find out if someone else already has a patent on a product, process, or concept that you're going to build or market. This is possibly the most complex legal specialty, and you should look for help from a qualified patent attorney. Your patent needs to be iron clad to protect you from the 'knock-offs' you may have to do battle with down the road. Like a patent, a trademark right allows the owner to exclude others from using the trademarked identity or from using an identity that is similar enough to cause confusion in others. If you have a logo or some other item that you plan on using as a symbol of your business, you may want to have a trademark search conducted to make certain that your logo or other item isn't already restricted.
Trademarks are kind of like muscles.
You use them or lose them. Not only should you use your trademark consistently to distinguish your brand from others but you should be vigilant about seeing to it that others respect its exclusivity. If you don't, your valuable identity mark may go the way of escalator, kerosene, zipper, yoyo, and aspirin - into generic limbo. Your role models should be Coke, Xerox, and Kleenex - militant protectors of their marks. Kleenex brand tissues, Xerox brand photocopiers.