Okay. If you're not playing random then it comes to choosing your civilization. Babylon is referred to as the best civilization to use when trying to achieve a science victory. The Great Scientist (GS) boost will help you from the beginning. However, you can use this guide on almost any civ.

When the game starts, you build your city. Anyone who has played will tell you to not move the settler and place your city. They're right. The AI is going to have huge advantages against you. Their science, production, city size, etc. will all be better than you. It's as if you are starting the game late.

First thing you build is a scout. One of the biggest advantages is knowing who and what is around you. In my game, i played as Babylon on the West vs. East map. I had France to my south and they rose quickly to become the number one civ for soldiers. Play your cards right, they won't attack you. Find out who's by you so you examine your threats.

You are going to want three cities only! And build them as soon as possible. Keep them close and near luxuries. Small civs help with world wonders and help you get science techs quicker.

Scientifically, start with pottery and get to writing. You have to get writing as soon as possible to get your bonus. Don't go for the great library, someone else most likely will snatch it from you. Proceed with calendar and philosophy and make sure you get the Oracle. That gives you a free social policy and a GS point which you will need. Proceed with militaristic techs to keep you safe. Try to get guilds early but make sure you can get education as soon as possible. Keep going with what you think is best for you. If you have threats, go for gunpowder. If you have coastal cities, go for sailing. You have to get them all anyway its the order you have to think through.

For social policies, you want tradition. Don't worry about building a monument in your capital because the tradition policy will take care of four free culture buildings. After tradition, do commerce and rationalism. The choice is up to you if you go more on commerce or more on rationalism. Commerce is necessary if your economy is crashing. It also does not need t be completed. Simply unlocking it is beneficial and landschneits are fantastic against the AI. The freedom ideology allows you to purchase spaceship parts. The order ideology allows you to use great engineers on them. These are level three tennets so you need to have good culture. Public opinion will be your enemy so choose carefully. If you can, get freedom.

Freedom ideology:
Avant Garde
Civili Society
Capitalism
Volunteer Army
Universal Suffrage
Space Procurements

If public opinion is favoring order which it usually does or if your economy is bad yet you have strong production, get order. This allows you to use great engineers on the spaceship parts. Remember you do need one aluminum per spaceship part so you have to get some either from a civ, city state, or from the recycling center building.

Specialists are the most important thing. If you don't utilize them, you will lose. Your capital should start with production focus. Know how to view city and change city focus! Production focus will help you get great engineers and help you build wonders quickly. Build two manufactory near the capital then switch to Great Scientists. Academies should be built all over. You should have at least six or seven when you get to the Apollo Program.

Libraries, Universities, Public Schools, Research Labs. Build them as soon as possible! Don't wait. Keep track of your science. By the year 1300, you should already have the industrialization tech and have should start building factories for ideologies. You have to be the first person to get an ideology so you get two bonus.

The world Congress can benefit you. World Fair is extremely important. If you or an AI propose it, vote for it. The second it starts, change your capital to production focus and work on the world fair. This will be a huge help for your ideology.

City-States are really unnecessary. It's already hard for the AI to win a Diplomatic victory. But be friends with the merchantile and culture city-states. They are more beneficial because they contribute to your economy and help you get Rationalism

War might be inevitable. BUILD AN ARMY! Do not forget about your army. In fact, you can ignore some buildings to build units. Buildings like constability and others are not needed because you will be behind in tech until the 1500s or 1600s. However, after that you should be tech leader. If not, you'll need to catch up with spies and must try to promote spies faster. If you stay at least third in soldiers, the AI will reconsider messing with you. The cash you have on hand also contributes to how strong you are. If you fear an AI, get them to declare war on another AI, You can trade war and peace like crazy and avoid a war. But if you get in a war, raze the cities. Unless it is extremely beneficial to happiness or the economy, raze it. Landlocked civs are easier to win with than civs with coastal cities. Coastal cities are also more costly because they do not grow as efficiently and require more maitniance.

Be smart. Explore, grow. Build farms like crazy to help you. Get great Wonders like Hanging gardens, Orcale, Ironworks, Big Ben, national college, hagia sophia, notre dame, etc. Get to the manhattan project fast. Get Uranium over oil because oil will not help you all that much in the late game. Worry more about building infantry in the late game then anything else. As the game ends, switch all cities to production and change the buildings to contribute to science. Buy great engineers and great scientists with faith and get the HUBBLE TELESCOPE. without it, you're done. Have fun and play smart!

Anyone questions? Feel free to comment below and let me know. And feel free to comment your favorite civ to play as and your least favorite to play against :)