Get a visa. The best way to work in Thailand is to be legal. If those wishing to work or live in Thailand choose not to do so legally, there are risks associated with this. For example, non-registered immigrants on a holiday visa (30-day visa) cannot register with their local embassy and are thus unprotected.
To get a visa the applicant will need to be sponsored as a skilled worker by a Thai company. This includes getting the offer in writing. At this point the applicant needs to go to the Thai Embassy and apply for a non-immigrant visa 30 days before departure, bringing all financial records at that time. At the same time, the employer will need to request that the applicant be given a non-immigrant visa. This enables the company to apply for a Thai work permit for the applicant. Thailand is big on "honor" and thus the company must vouch for the applicant, stating it knows the person to be dependable, upstanding, and law abiding. It must also attest to the applicant's ability and willingness to respect the laws and customs of the country.
Get married. If you have a special "tee rak" (sweetheart) in Thailand who is willing to marry, this is the best thing a foreigner can do. For this the applicant needs to go through the embassy and get a "non-immigrant visa" that after two years will become an immigrant visa. For this the applicant needs the Thai spouse's ID card, and three 5X6 CM photos, but nothing more. For all practical purposes a Thai couple in which one of the spouses is foreign enables the partner to stay for the trial period. Eventually the applicant will get a Thai permanent visa leading to immigration, and after 10 years at present, can apply for citizenship. The Thai spouse can take any job he can get and needs no special skills to work.
Open a business. Thai people appreciate work coming into their country. If the applicant has an idea and the means, he can get a visa to open a business so long as he can prove to do business solo or to hire a minimum of four Thai workers. Various fees are involved in opening a business in Thailand. These can also be "pay-offs" if the applicant is in Thailand trying not to leave and stay there under the pretense of the new business.
Just stay. Many people every year who come for a visit and decide to just stay. They may have met a friend who owns a bar or manages a hotel who is willing to pay them off the books so long as they stay legal. It is a great risk to a friend but a long known custom. "Visa runs" are an option if the visitor's initial visa for 60 days or longer has expired and there is no valid reason to extend it. A visa run requires you to fly in and out of Thailand every 30 days but enables you to stay as long as you wish. Oddly, there is no limit to reentries at current so this remains a favorite among many who want to live the Thai life.
