Scott is a certified home theater calibrator, having received his cert from THX, but ISF is also a good cert. He recently got a question about calibrating a BenQ projector for his home theater system. Where can he find one other than from Best Buy? Scott says that ISF has the contract to train Best Buy calibrators, but Scott wouldn't really worry about Best Buy. He would just get recommendations on who is the best in his area. He can also find a calibrator through THX.com or ISF.com under "dealers" by entering your zip code. It will cost you around $300 or more to get the TV calibrated though, more for a high dynamic range model.
If you want to do it yourself, then you could take the training course. There is an online training course that will educate you. TLVexp.ca is a great resource for that. But you will need the equipment, like a colorimeter. Scott recommends the XRite I1 Display Pro. It's $279. Plus software like Portrait Display's CalMan, which is $399. So for that price, you can pay someone more experienced to do it and get far more accurate results.
Another option is to buy DVE Digital Video Essentials HD Basics or Disney Wow, which will give you basic control adjustments and you'll get about 80% there. If you have a budget model, that's the way to go.