what to do before having trip abroad

The most important things to check are passports and visa requirements. In some countries you need a passport that is valid 6 months after your stay and not just during your stay, so check the expiry of the passports carefully before you leave. Double check the visa requirements to make sure that you have the lastest information, because those things change every once in while. Sometimes internet sites and guidebooks don't tell you the same things about visa requirements and the informantion seems confusing. This might happen, because part of the information isn't up to date, so it very important to make sure that you get the lastest information. In some countries you can buy a visa at the border and in som countries you will not be able to enter unless you have arranged your visa before you leave your home country, so always check the information before you leave.

Make sure you have your valid visas and current international passport, and don't forget to bring plenty of $$ (dinero) with you in the form of traveller cheque or acceptable currency (all mighthy U.S Dollar) while in Thailand and Vietnam if you want to enjoy the best of all things. That is all you need for both countries.

It would help to read ahead and learn what you can about the people and places your planing to visit. Have an itinerary on your trip and read about those places. The internet is very informative on these things. There may also be words and actions that are not rude on your language but is considered rude on those places.