Indeed it is a golden opportunity!

Allah said, at the end of those verses that talked about Ramadan: "So let them respond ˹with obedience˺ to Me and believe in Me, perhaps they will be guided ˹to the Right Way" (2:186).
If you did the right fasting and gave the right response, you will be well-guided. That is a positive change. 
What do you want to change? No human being is perfect, even the most righteous, everyone can change for the better. 
Thus all you have to do is set your goals (of areas you want to work on), and run the Ramadan machine. Why? Because the nature of Ramadan (its schedule, the fasting involved and its effects on the body and spirit, the Taqwa development process) will make that change come easy. It is like habitual training, but will work even more successfully because of the high spiritual charge. The main condition though is that your goals should be realistic and fitting. You don't have to achieve everything in one Ramadan.
Take for example, people who smoke. That's enough of a goal to try to change that habit in this month. In fact, it is so doable, due to the many hours of no smoking during the day. 
Changing a certain negative trait is another example. Prayer is described in the Quran as something that forbids or prevents evil (29:45), and there is a lot of that in Ramadan.
Finally, for change to take place, you must want it. "Allah will not change what's with people, until they change from within" (13:11)

For more tips on change during Ramadan, read below.