If you're in Bangkok, there is plenty of work teaching at language schools like Wall Street, Westminster, New Cambridge, the British Council. Mostly university students or working people who need to pass IELTS in order to attend a university in the UK/Australia/US. Most pay around 600-800 baht an hour. No need for a license, just a degree (for the work permit) and a decent TEFL like CELTA, or experience.