worlda daily: How can I spot a TEFL course that I should avoid?

Typical reasons to be suspicious include:

Only one or two centres offering that course
Tacky marketing, e.g. special offers and affiliate marketing (paying bloggers to recommend their courses)
Claiming to be accredited by or recommended by an organisation that doesn’t accredit courses (e.g. IATEFL or TESOL)
Mixing up accreditation and other things such as business partners on one page
Associations with dodgy online degree mills
Being asked to pay into an account that is in the name of a person rather than an organisation
Over-the-top claims about how well recognised the course is
Multiple websites
Very rapid expansion
Many negative online reviews