A lot of good tailors are located on Sukhumvit Road and near riverside hotels such as the Oriental. I paid about 120 baht for a tailored skirt. The New World Group on Charoen Krung Road near the Oriental is especially good. Some personal items you may want to bring with you are mosquito repellant, suntan lotion, deodorant, undergarments, and shoes. It is hard to find repellant and suntan lotion that are strong enough for Thailand, and the deodorant has a sickly sweet smell.
Some department stores sell American brands, but they are expensive.
Westerners will have a hard time finding undergarments and shoes that fit, and the Thai brands are poor quality. Krittika Onsanit, all rights reserved.