Confused with using article, gerund verb and noun

[Tsy]

I'm being confused about the usage of the article "the" when it is placed right after the word "of", what kind of situtation would we discard it ?

The amount of (the) RAM I have is about 2GB.
Should we have to have "the" after "of" in this sentence to specify that the RAM is mine ?

This is the title of a movie.

(The) war of (the) world(s).

How can I write these sentences correctly and properly ?
A design of the system for implementation of (the) GPRS on mobile phone(s).
A design of the system for implementing (the) GPRS on mobile phone(s).

Thank you.

[Lephuoc]

This is a good question, I guess. In my opinion, experience is the most important thing, though some rules can help us.

For instance:
The amount of the RAM I have is about 2GB.
War of the worlds.
A design of the system for implementing GPRS on mobile phone