Glad you're enjoying them - some quick tips
There's a boring early period of harvesting (yes, ME2 copied the boredom aspect nicely, well done), use it to upgrade your flagship with better maneuverability, speed, and then some weapons - you can avoid most early conflicts without too much trouble.
You will get upgrades and discover extra means of earning RU that will make gathering much quicker.
Once you have some upgrades, start investigating any and all rumors and sightings of aliens - there is a 'critical path' to the story, but its extremely flexible, and you can investigate all manner of side stories along the way, and there are some events that are entirely in your hands as far as how they turn out, some with extreme consequences.
If you're comfortable with Civ, you should have very little trouble jumping in here. Dig around online for a walkthrough or strategy guide to pick up on any areas that might seem obscure.
Ship construction and research can be a built overwhelming early (but in a good way!). Most new players start with Creative races, then graduate to others once they have a grasp on the research options.
Again, its pretty darn crusty. Assuming you do dive in though, a few thoughts.
The main reasons its awesome are a randomized limited tech tree (you don't get every tech every game, forcing you to play around their absence or acquire them via trade, espionage, or ground conquest (raiding factories for salvaged tech, essentially).
The second is its colony management - a handful of sliders and you're done. It seems 'too simple', but you will be grateful for it later in the game when it takes so little time to manage, leaving you to focus on combat, diplomacy, and expansion, the fun parts :D (this is exactly reversed from MOO2, which bogs down the later in the game you get due to colony micro - I play on medium maps rather than bigger ones for that reason).
MOO has very little in-game help however, so a lot of mechanics are extremely unintuitive. Check out this fan-faq: http://www.gamefaqs.com/pc/564694-master-of-orion/faqs/1927
Again, the OSG is actually really good and an interesting read, but tracking down a 15 year old guide for a game you may or may not like is probably going a bit far :P