How a company or organization can achieve a long-term sustainable growth?

Muhammad - basically any organization has2 approaches, Organic growth (by leveraging existing resources to work on more projects, providing internal career growth, enhanced customer satisfaction, etc) OR Inorganic (by acquisition, etc). 

Either ways, these are some check list items worth considering -

1. Customer focused: strategies on how to retain existing customers + how to attract new customers. 

2. Quality: focus on proven and tested quality methods - Six sigma (toyota example), available frameworks to catalyse better service, etc. 

3. entering new markets: worth a try to do some market analysis and start creating a new product (apart from its Core business), something that the company has not done earlier. And a well manager Portfolio on services and products offered. 

4. Consistency: a team exclusively overseeing that consistency & continuous improvement is seen. 

5. Sensitive to its employees' needs, growth.

6. monitor and control the processes by means of KPI's. 

7. Being Ethical: the very important point... 

this is not an exhaustive list... there could be much more which i have not covered here.. 

Best Regards, Ananth.