Here's a technical strategy (what to research and in what order at the start) that I snagged off of the MOO3 forums. The goal with this is to jump-start your research budget and economy at the beginning of the game while also providing you with enough fire-power to defend your holdings. The last game I played in hard mode, 8 races, huge galaxy, mineral rich, average technology - I had *zero* scientists after turn 100 or so and still stayed way ahead of the Psilons. The key to this was that I had 2x to 8x more population then the Psilons due to aggressive expansion during the initial stages of the game (lots and lots of colonies) before the galaxy filled up.

Starting technologies (do in this order)
(comp) Research Labs (150rp)
(const) Reinforced Hull (80rp)
(const) Automated Factories (150rp)
(comp) Neural Scanner (400rp)
(comp) Planetary Supercomputer (650rp)

Now, at this point, you'll have a good number of research points being generated, and you'll want to expand as fast as possible (every additional colony gives you many more research points). The next choices depend on whether you need defense immediately or if you can wait another 10-20 turns before getting pummeled by your nearest neighbor (keep your neighbors happy for the first 100 turns through trade, exchanging research, giving tribute or other baubles). In the early game, MIRV'd nuke missles are key (does 4x the damage of a regular nuke missle). Fire off your two salvos and retreat to the corners of the map (or jump out, leaving a scout behind). Each missle does 8x4 points of damage and you'll be able to fit 4 or 5 in a Cruiser class hull.

Defense (gives you MIRV'd nuke missles)
(chem) Dueterium Fuel Cells (250rp) -> Pollution Processor (650rp)

Production (boost the economy)
(const) Battlepods (250rp) -> Spaceport (400rp) -> Robo Miners (650rp)