1) Doing business in a foreign country is hard. Your two options are to target your new country or target your home country. If you target your home country, meeting with potential clients is going to be hard due to the physical distance and the time zone difference. If you target your new country, you're going to be at a disadvantage from a language and business relations perspective. Also, pretty much every country is inferior to the U.S. in terms of business development. Companies outside of the U.S. can be much more risk adverse and unlikely to do business with an upstart.
2) Getting a cofounder is really important. Moving to a different country can be lonely, and running a business can be stressful with a lot of failures. You need a partner in your business to lean on and to fill in for your weaknesses.
3) Have a good idea of your business plan before you start. You should basically have people lined up to use your product before you build anything. If you don't have that, it's likely you won't have a product people want once you build your product.