Uh... maybe it was just a terrible guide that was slapped together for the expressed purpose of separating you from your monies. There are way better places to get strategy tips for free.
gamefaqs and
apolyton come immediately to mind.
edit: The game is really about making choices. "Do I build this city next to the diamond bearing mountains or is it better to move it over just a little so I have sea access?" "Can I fight a war long enough to secure a source of oil from my enemy, or should I try to trade for it?" "Should my next invention be railroads to develop the infrastructure of my nation, or should I research nationalism which will give me a more powerful military unit?" There are basic strategies that you can try to follow, but each game is different.