We have a sideline in Surin Province with several Internet cafes. Biggest tip I can give you is find a place that has secure parking directly outside for cars and scooters somewhere handy to the big stores like Makro and Big C etc.There is roughly 47,000 people living in Surin City ... you are probably looking at a maximum of 1400 customers from this providing your prices are very, very competitive and you have been established for a couple of years. You will need to flyleaf about 14,000 households. It is all about price. My wife goes to a top-notch place and pays 75 baht. for a trim to cut split ends she says.
As Sangka says there are probably more salons than taxis, already with an established clientele and usually the whole family (ladies) will use the place. To drag them away you will need to offer something seriously good. Rents are high - do your sums. The average person struggles to make ends meet in Surin. You may be better off in Pattaya, Phuket, Bkk, Chiang Mai, or Udon or similar. There is a big farang village near the airport in Udon that might be a good idea. Americans, Canadians, Aussies mostly. There was no hairdresser there 3 months ago that we saw. Limited but steady clientele, put a salon in the house and get another job.