Wyndstar,
Thanks for your advice here and in other threads. I even spent a good amount of time reading through your past posts and there is too much great information for me to absorb.

As I mentioned, I did try a game using your 'all' and flip methods. I did everything you mentioned (i.e. sell tech for money/items, bribe enemies to go to war, extort, etc.) While I obviously need a lot more practice at it before I'm any good, honestly, it's not how I want to play a 4X game. It doesn't feel right to use factories to do research and labs to build ships. It feels like I'm taking advantage of the inner workings of the game engine. In addition, I constantly ran into the issue where deals don't make any sense. I basically end up experimenting with trying to trade tech, credits, treaties, etc. to see what works.
By no means am I trashing anyone's playstyle. I just want to play a 4X game the way I want to play it. That means a colony rush and building an infrastructure of factories/labs/economy to slowly develop my military and technology to eventually gain victory. That means tech trading. That means using diplomacy to create realistic deals to handle relations, build alliances and cause general mayhem.
At higher difficulties, the AI is given a lot of advantages, so it's up to the player to figure out how to overcome them. Unfortunately, if you play the game the 'normal' way, it's really difficult because the AI is doing the same thing as you. That's why 'out of the box' strategies become essential at high difficulties.
The 'all research' strategy works because it lets you overcome the AI advantage in research. This means you actually have techs that are valuable and you can trade for money/diplomacy/etc. Unfortunately, it's a gamble because you are sacrificing your military/social production in order to gain a significant research boost.
Similarly, 'all factory' works because you are focusing your efforts and sacrificing research in order to overcome the AI advantage.
In any case, for me, this just means I need to experiment with game settings until I find one where the AI is difficult, but the trade mechanic works as I expect it to work.
(Ignore my ranting, heh. I've been playing Civilization for the past year and only recently switched over to GC when I started to get bored with Civ. So I'm practically a newbie again, so I'm sure some of my ranting is off base and just means I have to adjust to playing a new game.)