Essentially, there are 3 ways you can go about learning New Testament Greek:
1. You can take an in-person or online class.
2. You can ask someone to tutor you.
3. You can study on your own.
Remember that no approach is necessarily better than the others. It makes a big difference to know your personal learning style. It should also be noted that all good things often take time, so don't be too quick to dismiss the possibility of studying Greek if you haven't given it a chance!