In general, I was quite well prepared for my move having researched Thailand quite a bit leading up to my journey. Something I would advise anyone wanting to live and work in Thailand is to be prepared for the very real culture shock that many new expats experience.
Those coming from first-world countries should be prepared for a more laid back culture (almost frustratingly so) and relentless bureaucracy (Immigration Departments leave much to be desired). Other than that, it's important to keep an open mind and to understand that Thailand is a country with its own customs, culture, religions, and people and that these elements should be highly respected. Be a good guest. Embrace the difference, don't let it deter you.
Many participants expect a "working holiday" type of experience, but this couldn't be further from the truth. Most weeks are quite similar to a full-time job in my own country, the only difference being the job description, colleagues, surroundings and of course job satisfaction. Getting up for work (very little traffic in most instances, excluding Bangkok for obvious reasons), attending morning meetings, teaching my allocated classes and then commuting home (if I haven't got a scheduled tutoring session after school).
Most days food is bought at local street food vendors or restaurants, simply because it's cheaper to purchase cooked food than to cook every night. This has allowed me to try many different types of meals, sinking me deeper into the Thai culture I've come to love.
Weekends are when we are able to travel; visiting nearby nature reserves, islands and many other "touristy" attractions. Thailand has many long weekends due to the large number of public holidays here, these weekends are perfect for venturing out a bit further -- whether you want to travel deeper into Thailand than usual or even further into neighbouring countries, there is more than enough opportunity as well as a public transport system that caters for exactly that.
I didn't fear coming to Thailand. I feared staying in my tired old routine. If you're coming to Thailand with fears, you're doing it wrong. If you fear change, then ask yourself if your fear of change outweighs your fear of never experiencing something new and different, with all of its nuances. It's simple.