A few tips for starting out in Supremacy:
1) Build up one planet with a bunch of construction yards in a sector. Use this planet to FILL another planet with shipyards. Basically build dedicated ship building worlds or ships, especially bigger ones take a billion years to finish

Same applies to troops but they dont take as long so you dont need to go as over the top (I try to get a planet in each sector with at least 12-15 shipyards on it

), maybe two if I want a REALLY big fleet.
2) Use the characters. ALOT. Send every character with any kind of half decent diplomacy rating off to convert worlds to your cause asap. Send the good combat characters off to sabotage stuff. Special notes: Never take Palapatine off coruscant, as long as hes there he grants a bonus to ALL imperial forces in the galaxy. Any charactere travelling as part of a group with Han Solo are travelling on the Millenium Falcon and travel twice as fast as normal. This can be invaluable for making quick recon runs or sabotage missions.
3) Colonise uninhabited systems. If you find a planet with no population (as with most of the rim sectors) if you land a single troop on them you gain that planet. As soon as youve build 1 building there then the planet gains a 100% loyal population (and you can remove the troop if you wish).
4) Sabotage expensive things early. At the start of the game the Imperial player will generally have at most 1 or 2 Imperial Star Destroyers (usually only 1 and some VCDs). At this stage it will take well over 100 'turns') to replace that ship (quite aside from the cost!). If you can get Han and Chewie on a sabotage run with maybe another character and a commando unit or two running a diversion you stand a good chance of blowing said ship up outright. I did this once (and thanks to hans special movement speed rule this was within the first 20 'turns' of the game) against a friend of mine over our network at uni and got a phonecall.
"Hello?"
"AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!"
"yeah sorry about that

"
:twisted: