Hacking games

Hello

I am intrested in making hacks for games. I have a little background of c++ and win32 programming.
I recently downloaded cheat engine and tried it on games . One was very simple game (like sim city) and that was easy to hack with cheat engine.
Next game was Age of Empire 3. With that game i had problems , couldn't hack correctly i will probably give another try tomorrow.

Anyway , i actually want to study hacking games which use online server . I dont have much knowledge of this and if any of you can explain me how this works . I actually don't know exact questions to ask. I just need some information to begin studying about it . I know that c++ is important for making hacks , but how can i change information from online server ? And what other things are what i have to study . Direct3D probably ? I have seen and used D3D hacks .


Thanks in advance and sorry for my bad english language,
Minaset.