It is not straightforward and you need equal amounts of perseverance, luck and tact. If you just had kids (like we did) and plan on doing it remotely, think carefully twice! You also need to be prepared to learn everything about everything where construction is concerned.
But you can minimize it if you do your homework. The internet is your friend, but you have to dive deep.
This is a tricky one as you won't know till you've tried. In general, it is a good idea to hold on to part of the payment till everything is good and delivered. There can be an exception for large, well-established stores.
Our contractor is paid according to progress after we negotiated a price for the build and placed a deposit of 20%, the sum of which is insured.
Being in Singapore, we found surprising links to the country through mutual friends and family. Even if it's not in a field directly related, it adds to your pool of knowledge. It also helps to have someone local (and trustworthy) aside from your contractor whom you can rely on to check in on the site and follow up on the endless to-do list.
This will help you get ideas and learn more about what works in practice. For example, open bathrooms are great but would you want to share your shower with the abundant wildlife? A bonus if you have contact with the owner whether local or foreign as they are usually keen to share their experiences with you.
Our experience with Sri Lankans have been overwhelmingly positive--they are kind and friendly people who are driven by their Buddhist or Christian spirituality. While they appreciate the economic benefits of foreigners coming to their country, they are proud and nationalistic people and won't respond well to condescension or impatience. Our real estate agent also advised us against expecting 'Singapore time' (synonymous with 'New York minute').