Greek is tough. How can I finish?
You need to pace yourself.
Here's an analogy. I just drew this picture.
Let's say you're a bus driver and your route goes from point A to point B with several stops along the way. A good bus driver isn't one who gets to the end of the route in the quickest time possible. He's one that hits all of the stops along the way, at the right time. Basically what I'm saying is that's how you should approach the study of Greek. Never bite off more than you can chew. If you do, you're just going to burn out faster and increase your chances of falling off the wagon.
Let's say you got a bad grade on last week's quiz. Well, determine to do better next week. If you did great on last week's quiz, then repeat that effort. I haven't found a mortal who couldn't finish a year of Greek. You already have everything you need to be a Greek student. You see, once you decide to see it through, your quest centers much more on tenacity than talent. It's your mindset that separates those who do from those who dream. There's no magic secret. You just persevere to get results.
The finish line, like the truth, is out there somewhere. All you have to do is carry on.