1) Choose a company that understands your language. If you know English, make sure that you are working with folks that are good at it.
2) Do your paperwork. Document everything. Create separate email threads for different things.
3) Use a project management system like Basecamp. It will help you create tasks and threads that will avoid confusion.
4) Whether you are ahead in time zone or behind, there will be time slots that will be good for both. If not, ask your partner how they will figure out the timezone. If they look helpless, just make sure that everything from your end reaches them before they begin work.
5) Meet the core team at least once to minimize the distance element. Fly to their office or invite them over to yours. Trust me, it will make a world of difference.

You will figure out whether the guys you are dealing with are professionals or not during the initial communication only. If their replies take too long and aren't comprehensive, give them a skip.

Also look at work case studies. This is super important. This is how case studies look like, https://www.upreports.com/free-reports.html

I hope this helps.