Lately I've received multiple inquiries on how I'm actually traveling through Asia in the next couple of weeks and about basic visa requirements from country to country. Border immigration seems like its main purpose of being built is to keep you out of the country you are trying to visit. Regulations can range from paying a small toll fee to enter a country for a short period of time to having to prove financial assets and property back home to get that little stamp in your passport. And if you're anything like me, the latter is near impossible to accomplish for the person on a budget. While visa requirements can differ greatly from the country you are coming from to your port of destination, there are a few general tips that will save you lots of pain and exhaustion later on.
Most countries throughout the world allow travelers to enter their country on a "tourist visa" usually for around 90 days upon each entry. These visas are stamped as you leave your port of entry (ie. the airport). There are some places that are an exception: for Americans traveling to the Philippines an American can get a tourist visa for 21 days max. If you plan on overstaying your initial visa, speak with the nearest immigration office and alert them to your situation, but be prepared to pay a small fee to extend your visa. Another option is to take a short trip out of the country you are in and return the next day. A friend of mine teaching English in Chile did this for years, where he would cross the border into Argentina and then come back into Chile and bypass this rule.
For American/Canadian and most other European travelers, I recommend exchanging currency in the country you are going to for better rates instead of your own country. American airports are notorious for scamming upwheres to 25% extra on the exchange rate. Packing light has its benefits too particularly when it comes to clothes in the subtropics. A decent wardrobe in some locations in the world may cost you $20 USD, well offsetting the costs of that extra piece of luggage you would have brought onto your plane.
Though there is a lot of arguments of carrying your passport on you vs. keeping it in a safe place, use your best judgement. If you don't put yourself out there as an easy target for theft, then keeping your passport is highly advised because if you are caught without it, you may not have the opportunity to grab it from your hotel room if you're stuck in a cell.
One thing to note that on a tourist visa, you are not typically allowed to do business in the country you are inside. That's not to say that you can't do work under the table, but for the most part you'll need a "business visa" and a sponsor if you plan on working legitimately. Many people find working abroad as they travel to be very satisfying and there are a select few that choose to make an entire life out of it.
To apply for a visa before you visit a country, you will have to visit the Embassy or Consulate nearest to you and present lengthy documentation for that stamp. This can include (but not limited to) medical records, financial assets and accounts, contact information of people you may be staying with abroad, multiple 2x2 inch photographs of yourself, and of course your passport.
Other places have special rules, such as several Central Asian countries will not let you enter if you have a visa stamped from Israel. In cases like this, you can usually request a second passport from your country's immigration office to bypass such rules.
Breaking immigration and visa rules should not be taken lightly, as you may quickly find yourself in a prison cell in a foreign country and/or deported. ALWAYS adhere to local customs and laws--what may be legal in your country may not be elsewhere. Another thing that I feel must be noted is that drug possession and trafficking does NOT pay off in a foreign country, heed my advice and just don't do it.
If you have concerns about your trip to a foreign land feel free to comment and write back to me, even if it seems like a simple question. Thank you for your time.