In my opinion the main problems during the development process of a game are 
-the motivation = When there is nearly no progress, you will loose the motivation -> so try to set small goals so that you always think that you have reached/made something amazing
-the team = good teams should be well structured and all the members should “fit” together (the best team would be comparable with a group of friends
-the game = you should have a clear goal in front of you, because otherwise it will be pretty difficult to finish the game. e.g create a GDD with the rough outliners of the game