When your are playing and mosue over your current score it will give you a message with something like "total score for winning this turn" I am not sure of the math or formula but just from observing to two BIGGEST factors in your score. Is how early you win and how big a population your civ has when you do. Like the longer you take the better it is to have more people in your civ to try and make up for it. All the other things that can add to your score like how many wonders you control or how many techs research dont really matter. Things like that dont seem to affect score more than few 100 points either way but the time and your population can affect your score by tens of thousands of points.