This works at lower levels of difficulty (ie, not emperor or deity):
First, pick a civ that is scientific. Get the goody huts by exploring. Set your science rate until you lose money and then back off one notch. Early on, you can set it pretty high with no deficit, but it does little to reduce the number of turns.
You want to get libraries and universities ASAP. Establish contact with as many civs as soon as possible. Sell or swap techs with them. Remember to offer, do not try to setup a deal--they will reject it. Funny, they will reject something that they will offer themselves. I guess this is a exploit, but what the heck? I once got 380 gold/turn for sanitation. England and France seem to be the most generous in this regard. Use the funds to build a little mil and the rest to crank up science. Make a beeline to republic and then to democracy.
If possible, build copernicus's observatory. This wonder has no expiration, and doubles science in the city in which it's built. Once you've gotten libraries and universities in all your major cities, changing science spending will affect the turns per tech considerably.
Once the income runs out from the sales, make your rounds again and sell them the new techs you have researched. You can keep this up until nearly the end of the game. If the other civs are warring, the income from brokering techs will drop considerably. Adjust your tactics accordingly.
Make a beeline to computers and build research labs in all your major cities. It will take you forever to research a tech like superconductor without them. Research labs are dirt cheap with a science civ.
Some pointers:
Dont sell a tech that enables a wonder until yours is nearly built. This is evil, and i laugh all the time.
Of course, if they are able to switch construction to another wonder and have accumulated sufficient shields with the prior construction, you may get burned.
Avoid war if at all possible. This kills science research AND culture. Avoid war mobilization unless things are dire.
BTW, what is a "soak"?