Is it right that English is most important factor to success?

After 3 years of working, I recognize that despite well-study, monthly I ,even working at international company,only get the salary which meets basic needs. In these day with Vietnam 's economic, we can't go rich without doing own bussiness. I received the advice that is to try studying english well to get more oppornitys. In this network, there are many successful peoples, could you teach me how to do next while i am just a fresher.