How can I extend my 30-day visa on arrival in Bangkok, Thailand?

Noel, originally from England, is currently in Bangkok with a 30-day visa on arrival that is about to expire. He seeks guidance on how to extend his stay for another 30 days, including where to go, the costs involved, and whether the process is straightforward. Responses indicate that he should visit IT Square, Laksi Plaza, on the 3rd floor at Counter K to handle his extension, and that it's advisable to make an appointment due to the volume of applicants.