Here's usually the strategy I follow, of course I often tweak the sliders every turn.
1. I usually play Terrans or Alterians. And like above, federalists or technologists. I tend to always choose creativity, and extra population growth (this helps to bring in cash faster), then choose either economics or more research. I prefer technologists because you also get +1 to sensors which is helpful early on spotting planets to settle. In beginning of game, always set your total production slider all the way up to 100% and leave it there! Never take it down. If you are going broke, research and build economics, or quit building military on some of your worlds. Trade your Influence points for AI's gold! (<-- do that before trading tech's for gold), trade influence points for AI spacecraft, and trade Influence points for their tech's.
2. Factories are expensive, build the minimal amount of them until your economy picks up! Initially during colony rush, I build ONLY 1 factory, 1 recruiting center, 1 starport, then any appropriate buildings on special tiles, then all economic buildings. On earth (starting planet), I will build at least 3 factories (usually rush build the first one), build the special unique starting improvement (terrans gives +1 speed and some other stuff). I initially set the sliders to high social production to get Earth's factories done and unique improvement done. Once those are completed on Earth I set the social slider to 0. and set military/research to a 70/30 ratio (but I change it every turn to make sure I get best colony ship build time). For the rest of the game, I leave social production at 0, and use FOCUS on planets that need to build social improvements. This goes for all newly colonized planets.
This way Earth can spit out a colony ship every 2-3 turns, and you will still be getting good research in. Eventually once colony rush is done, my slider ratio tends to gravitate towards a 50/50 ratio (military/research) as more expensive techs need to be researched.
3. Build time is not quite as important on immense maps or larger maps. Newly colonized planets will build a factory in around 10+ turns, I just let them do it. I use Earth as the primary source of colony ships, and I usually grab many planets this way (more than my equal share's worth, even on Suicidal difficulty).
4. I tend to research tech's that give +bonuses to economy, social, and military first. Playing as Terrans, I research to Universal Translator first, because then I can use my diplomatic power to my advantage in trades. Xeno Engineering usually comes next, along with Planetary Improvements, Galactic Warfare, Space Militarization, Xeno Economics.. then I usually beeline for Sensors to get Eyes of the Universe. After that, I tend to try to get to Interstellar Republic and more Economic buildings to help my cashflow.
5. After colony rush is complete (or during), I start my constructor rush to grab resource mines. The planets with highest production will make constructors, while other planets will make cheap little Star Fury's for basic planet defense. If I have very few resource mines, I will use constructors to make economic starbases, and I will also make freighters. This is usually the 'I need more money and will do whatever I can so I don't go broke' phase. After this though, once my economy starts picking up (usually after 1-2 years), there's nothing else to build but military and more constructors, so that's all I build for the rest of the game. I try not to start a war until year 3 into the game, when I have a firm footing, but if it happens before, I just deal with it the best I can.
This way, most all planets will have their focus on social, but will still be producing military and giving a fair amount of research. You will research quite faster having 50/0/50 than having sliders at a 33/33/33 setting. And your production will also be better overall (I have tested both, 33/33/33 is the worst thing to do). In fact even the AI uses the 50/0/50 setting and uses focus for social.
For Maso difficulty and above, you need to use the influence point trading scam on the AI to survive. The AI greatly values 999 influence points and below. You can get ALOT for IP's!