Hello.im currently living in north eastern thailand on a tourist visa and i would like to change to a non b visa to be able to work.i already have gotten a teaching job.thus was requesting info on how do i go about it and can i change my visa without leaving thailand.my tourist visa exp on 25th aug.please advice

You can only apply for a Non B Visa at a Thai Embassy/Consulate.

Certain nationalities can only apply in their own Country, so knowing your nationality would help.

 

http://www.mfa.go.th/main/en/services/4908/15388-Non-Immigrant-Visa-"B"-(for-Business-and.html

You can do a change of visa status from a tourist visa entry to a 90 day non immigrant (category B ) visa entry at some immigration offices. But you must have 15 days remaining on your entry to apply for it. It seems you may not have enough time to do it unless you can extend your 60 day entry.for 30 days.

See here for the requirements. https://www.immigration.go.th/content/service_73

Since you are in the North East it would probably be easier to apply for the non-b visa at the embassy in Vientiane or the consulate in Savannakhet.

Vientiane's requirements are here. http://vientiane.thaiembassy.org/upload/pdf/Visa/Non-B teacher.pdf