Know the four phases of culture shock so that you can be aware of which phase you are in while you're traveling abroad. Phase 1 is the "honeymoon" phase during which you will feel excited about all the new things you are experiencing. Phase 2 is the "frustration" phase in which you begin to feel homesick and yearn for the way things are back home. At the same time, the new customs and habits in the new culture may become irritating to certain degrees. Phase 3 is the "understanding" phase in which you start to feel more assimilated to the culture. Phase 4 is the "acclimation" phase in which you will have developed new routines and habits to effectively coordinate being in a new culture and finally feel a sense of belonging and that everything is okay.
Learn as much as you can about the new culture before traveling abroad and while immersed in the new culture -- especially by practicing the culture's native language.
Try not to get offended or irritated by facets of the new culture, and don't offend anyone in the new culture -- be as open-minded and respectful as possible.
Take time to rest and recuperate from spending time within the new culture. You can do this by seeking out activities that are familiar to you and other people from your home culture.
Know that after spending a lengthy time in a new culture, it will no longer feel new and you may experience reverse culture shock when returning to your home culture. However, you will return to your home culture better educated with a wealth of new experiences, perspectives and understandings.