Computers Can Help
Learning Greek means memorising things. There is no way around it. Without knowing vocabulary, and recognising from memory the common grammatical forms, it is impossible to read Greek.
The secrets to memorisation are: little and often, and interactive. We are all tempted to leave things to the last minute, but while learning 10 words a day for two weeks is possible, learning 140 the night before the test simply isn't. There are many ways to make learning interactive such as working with a friend, and using computers.
Computers can be a great help. They do not get bored, they don't get frustrated when you get the same word wrong for the tenth time, and some can remember which words you need to keep coming back to. Many people also find learning on a computer has a certain 'game-like' qualitiy, which means you can do it for hours.