The main mistake is to forget about what the European Union and the Schengen Area mean. Instead of going for one of the Golden Visa programmes and getting a residence permit of Portugal, Spain, Malta or Latvia, people keep trying to get a residence permit of Germany, France or Italy. In other words, they choose countries which are already overcrowded with both legal and illegal migrants. Besides, you will be required to stay there legally for 10-12 years and spend a lot of time and effort in order to gain citizenship.