Welcome to the forums, SilverBleeder!
The short answer: empire management. Primarily, science is a function of commerce. (You can also use specialists to generate science, but that's a different discussion). The more commerce (gold) your empire generates, the more potential science (beakers) your empire can generate. I say "potential" because there's a slider found on the F1 screen that lets you determine how much of your per turn commerce is dedicated to science. You can put anywhere from 0 to 100% on science. You can generate more commerce (&, consequently, more science) by: having your workers build more roads; making sure your citizens work roaded tiles; and making sure your citizens work riverbank tiles. I'm sure there are more ways, but those are some of the primary ones.
Also, trading techs is important. This will not only get you techs without researching them, but it can also hinder the AI's ability to research.
If you are playing at Chieftain, it's important to understand that the AI gets totally crippling penalties at that level, which slows the tech pace down to, well, whatever pace you set. As you move up in difficulties, you'll see the tech pace increase pretty quickly.
Edit: Wow. I just got triple x-posted . . . I really need to work on my long-windedness.