No matter what you do things can and will go wrong if you don't hire the right builder and have an iron clad contract and a very good lawyer (for when things do go wrong).
We built two homes in Thailand, one with a European builder and one with a Thai builder. Both times I designed and drew the homes but then got a civil engineer to do official drawings. I was very careful and either me or my wife (or both) were on site every day of the building and still there were lots of problems. The Thai built home turned out much better quality than the farang builder's and was delivered on time, but it had almost 100% cost overrun which we did not cover for properly in the contract. The farang built one had huge cost overruns, serious quality problems, and took three times the length of time promised to deliver (two and a half years!). In fact it would probably still not be finished (12 years later) had I not fired the original builder and finished it on my own hiring sub-contractors. Luckily on that one my contract covered the cost overruns with a daily late penalty clause so the initial cost was contained and the only overrun I had to pay was for the sub-contractors to fix the mess the original builder made.
Just be careful who you hire. Do your research and homework on the builder and materials (insist on a detailed bill of materials and follow up by checking that the quantity and quality matches the list), and get a contract written to cover anything that can go wrong. Then either you, if you are knowledgeable, or a trusted hired professional must monitor the work daily.
One additional point. Be careful where you build. Make sure there is nearby access to utilities, and if there is any empty land adjacent or nearby be very cautious. We built our home in Hua Hin with empty grazing land around it. For the next 7 years there was construction going on on all sides. There was constant noise and dust and they ruined a good sealed road which got so potholed by the end that my wife's sedan could barely make it to the house. The walls they put up caused flooding (mudslides) to inundate my driveway every time it rained hard that would take days to shovel/wash out. Also, as there are no building codes you could end up with a chicken farm or fish sauce factory next door.
Thailand is a great place to visit, but I wouldn't want to live there...