A lot of times I notice that students make some mistakes regarding the stress of the word. I always say, pay attention to the stress. I know that it requires a shift in how you read the words and the text but think about it. You can transform this weakness into your own strength. You might come across a new Greek word, you have never seen. By paying attention to where the stress is in the word, you will be perfectly able to pronounce and stress the word, unlike let's say English, where that is not the case. And stress is really important in Greek language!
Have a look at the examples below:
πότε / ποτέ (when / never)
Αθήνα / Αθηνά (Athens / Athena)
θέα / Θεά (view / goddess)
You will sound much more like a Greek, just by saying the word with the right stress!
So what's the point? Don't stress about the Greek language. It is easy. It is just a matter of stress (among other things) ;) :)