But more specifically, Slynky is right. The key to rapid expansion is to get the new colonies producing new colony ships as soon as possible. There are not a lot of things you can do in the first 10 turns to get a huge lead. At the end of ten pretty much everybody will have close to the same number of planets, assuming a roughly equal start. But the fast expander will put those colonies to use building space yards and colony ships instead of research and resource facs.
Here's how it works:
At turn 10 the F.E. player has maybe a couple more colonies then you and maybe 2 or 3 space yards while you have one, maybe 2 space yards. Doesn't seem like a big deal since we are only talking about a couple planets. But that's a 60% increase over your rate. If that holds over time, and it will, you will be way behind.
At turn 20 the difference starts to be noticable. The F.E. has close to 20 planets. You might have 15 and probably don't think you are that far behind, but you are way behind in truth. The F.E. player has 8 to 10 space yards on his 20 planets, some of which are already building colony ships. You might have 3 or 4 yards on your 15 planets. You are in trouble and don't even know it.
How does he afford this? Well, honestly you can't have everything. If you look at all the numbers he is probably behind you in research points right now. Also he's probebly built some mineral faciliites on planets with 75 to 80% minerals. Something you wouldn't even consider doing. Also he likely hasn't built a single ship that isn't a colony ship or a population transport. He does his reconasance with his colony ships. He also might have to put queus on hold form time to time, but that's ok. Even with partial queues runing he is outbuilding you.
If you happened to show up in his homesystem right now he'd be toast. But you wont, because his space is twice or three times the size of yours by now. Everywhere you look along the borders you find more of his planets and colony ships. You naturally assume this guy is not someone to mess with, so you don't even try. And if you do he's got a lot of space he can trade for time to prepare his defenses. By the time you can assemble your fleet he can put a swarm of destroyers in your path. Even if they are lower tech they are going to chew you up and make any victories very expensive. Keep in mind this is turn 20, so your tech ain't all that either.
By turn 30 he has twice the number of planets you do and is building 4 times the number of colony ships. Also he's catching up in tech because he can devote more to research. And his resource problems have all but dried up. Having planets to burn will do that for you.
By turn 40 he has four times the number of planets you do and is building six times as many colony ships cause he is still making space yards.
From then on it just gets ugly. You are playing a different game then he is. He has you beat in every statistical Category, most of them by a large margin. You can either become his vassal if he wants you, or you can try to make an alliance with the other empires to put a stop to him before he swallows you all up. But it isn't gonna be easy. Noone is going to believe he is all that big this early in the game cause they don't share a border with him like you do. They will figure he is jsut the phantom bad guy you are using to scare them. And he will feed into that of course and buy off their allegience and you might end up being on the wrong end of the alliance.
Better luck next time.
Geoschmo