A country develops when its capital and manpower are fully utilised. In the past there was shortage of capital and it was utilized fully. However, black money was remaining mostly idle. Manpower was not fully used as there were not many avenues for employment. The best thing to have been done is allow black money holders to bring out the black money with some assurances and some concessions and encouragement. If this had been done there would have been no need to resort to demonetization.
Now what is to be done is to ensure that black money is not created by reducing corporate tax. Income tax rates are already low, compared to rates in many of the developed countries.