If I had just one piece of advice to offer people - do NOT arrange jobs before you get here. Come over to Thailand, get yourself settled in and then take the time to weigh up your options.
Many schools aren't interested in hiring or even corresponding with teachers who aren't already living in the country. Teachers plans quickly change. The guy sitting in Canada who shoots off a few speculative e-mails and accepts a job at a school in February won't necessarily be around for the start of term in May.
Schools have wised up to this so they much prefer local hires. When it comes to finding a teaching job in Thailand, nothing beats actually being here and pounding the pavements, arranging interviews and knocking on a few doors.
When I wrote an article on the most common mistakes that new teachers make when they come to teach in Thailand, I put this right at the top of the list. Have a read of the article to get some more advice.