Regardless of your clothes, you will probably stick out as an American tourist. Differences in American life and diet result in different physicality, movement and habits which will be apparent to many observers. But if you want to try to blend in, once you arrive, go to a clothing store that the locals shop at, and buy the clothes you observe the locals wearing. When in doubt, solid tan, white or dark color shirts and tan or khaki pants are relatively universal, not to locals, but to travelers.