Hahaha.. I never really learned it officially or go school. Just pick up from listening then trying. Listening to Thai songs with translation or Thai shows with subs also helped me understand and pick up key words. Key thing is to TRY. Just force yourself to understand and reply in Thai when spoken to.
Not saying I can fluently speak or understand everything but enough to get by normal convo with FL, ML, also fun to interact with pretty and hot girls in the club.
But the best part about being able to speak some Thai is shopping! Sometimes the shopkeeper will open with "Farang" pricing, but if I then reply/speak in Thai they give discounts thereafter. Restaurant aunties will sometimes throw in some free dish also, if I flirt enough lol.