How to extend Thai Visa?

Most people do a visa run when their visa is about to run out. This involves catching a bus all day and then riding a ferry over to Myanmar to get your passport stamped and then coming straight back. It's boring and will allow you another 30 days and costs about 1300BHT. Or you can just fly to Malaysia or somewhere close like that and arrange it at Thai embassy there, which should give you another 3 months.