One game completed already

Within two days, I have already completed one game of Civilization IV. This was the first time I ever played a strategy game on the computer, so I was not expecting any special achievements in my first attempt. I decided to participate under the Roman Empire, naming my leader Marcus. As soon as the game started, I had no clue what I was doing. I simply chose all the recommended activities, while focusing on my military power simultaneously. My strategy was to develop guns, germs, and steel. After having read several chapters of Diamond's "Guns, Germs, and Steel," I was convinced that this would be the best approach. Diamond puts forth strong evidence of the positive effects of guns, germs, and steel. Those countries which first developed food production, along with animal domestication, were those who were the first to develop germs, the most deadly weapon of all. In several wars, germs killed more enemy soldiers than guns and other military weapons combined. The production of food would lead to the domestication of animals. These animals would then bring germs, and finally, guns and steel would be produced. As one would imagine, an extremely dominant country would be the result of this strategy.
Unfortunately, my masculine aggressiveness caused me to become too eager for battle, and as a result, I focused on developing a strong military in order to declare war on the weak, attempting to expand my territory. As one could imagine, this is a poor strategy (and I'm sure that Diamond would be the first to tell me). At first, whenever I was asked to declare war on the other leaders or decide to have a peaceful relationship, I would immediately choose the latter. Therefore, I was off to a quick start, and I was in the lead. After I gained confidence in my military and grew accustomed to the game, I decided to declare war on the Germans. This was a miserable decision. It seemed as if everyone was progressing much more quickly than I, and as a result, my cities were being taken over. I immediately attempted to cooperate with the Germans, but their leader refused as a result of his anger. Eventually, I was able to produce a cease fire pact with him, and therefore was able to work on my goal of acquiring germs. Next, I decided to make decisions based on the growth of my economy, hoping it would lead to the establishment of germs. However, I once again wanted to start a war as a result of boredom. I sent every single member of my military to the walls of the opponent's (the Persians) main city, attempting to overpower them. Once again, I had no success. My marines were demolished by enemy tanks and planes. Finally, I restored peace with the Persians, but it was too late. I had failed as a leader as a result of an aggressive personality and my failure to pay attention to Diamond.
I plan to immediately begin a second game, and will focus on producing food immediately. I will not roam around the huge map trying to engage in wars, but I will focus on the wise advice of Diamond. All that needs to be done is follow a few steps:
1) Produce food (which leads to more people as well)
2) Domesticate Animals
3) Establish germs as a result of the animals
4) Boost the growth of my economy
5) Adopt the techniques of guns and steel
6) Civilization domination