General Walkthrough

This article contains the general walkthrough, which extends the Quick Start guide but does not provide specific step-by-step directions on success or playthrough.
If playing Starcom: Unknown Space for the first time, or if you are not an experienced player but have some familiarity with Starcom: Nexus you may wish to:
* Read through the Quick Start guide and familiarize yourself with what to expect ; and
* Optionally skip past the game's basic tutorial by loading one of the Arrival Complete or Post Prologue saves
Familiarize yourself with the seven rules described in the Quick Start guide. For convenience, they're repeated here:
* Save Early, Save Often. 
* Listen to your first officer. Why? Your first officer knows more about the ship’s operations and how to manage your crew than you do. Being the Captain, however, you’re free to make as informed or snap decisions as you like.
* Read everything. Why? The game provides some clues and subtle tips about how to win, without necessarily instructing you through your command crew or mission goals.
* Talk to everyone until you exhaust any new dialogue with them. Why? Beyond providing information, the game may not progress you from one point to the next unless you’ve read a particular bit of dialogue.
* Scan, investigate, interact with, and survey everything possible – especially before you fire on it. Why? You actually progress faster than if you just blast your way through every encounter. True, you can get an infinite amount of resources just by reaping spaceship debris or analyzing artifact drops from destroyed hulls. However, you’ll progress faster if you focus on Starcom’s primary mission (peaceful exploration) than if you go on the warpath. Also, because you gain command crew experience points by completing encounters, this is the way your crew will become more proficient at their specialties.
* Activate any Remnant Gateway you come across. Why? There’s no penalty to leaving a gateway activated or inactive, but inactive gateways you didn’t discover through some kind of scientific method (mission rewards, dialogue with factions, etc.) won’t show up on your map as destinations to travel between. Better to activate them first instead of forgetting. Think of them as waypoints or checkpoints.
* Be nice to people & make allies. Why? Beyond the obvious (Starcom being a peaceful organization) you will need trade partners and allies at the start of the game, and at the end of the game as well. 
Take your time in completing the first four missions and save frequently as you progress to completing Beyond the Gateway
You may observe, for example, that your ability to move around the map and collect resource drops (from hostile ships, from asteroids, etc.) is limited heavily by the following:
* Tractor beam technology
* Engine technology & overall thrust
* Reactor output to power engines, or weapons, or both
You should therefore focus on the following technologies & try to use the exponential nature of growth (Faster resource accumulation -> quicker ship expansion & upgrades -> faster resource accumulation, etc, etc.)
# Tractor Beam Splitter & all dependencies (all technologies possible in the Tractor Beam technology branch)
# Trade Analysis (as early as available)
# Battlestation Training
# Resource Spotters
# Artifact Spotters
# Plasma Fire Support
# Sensor Calibration & all dependencies
You'll also note that there's no specific penalty to triggering a game event (such as a minor discovery, an anomaly which carries no risk but grants a resource bonus, etc.) and then just returning straight home to see if you can make use of the resources or RP. Feel free to do this as often as you like.
Beyond the Gateway suggestion (spoilers!)
 
The star to the southwest of the constellation is a convenient way to encounter an early game anomaly and also gain rapid RP without much risk.
 
On completing Beyond the Gateway proper, ensure that you have scanned, surveyed, and hailed everything you can approach safely.
Suggestion: (spoilers!)
 
Where possible, start the Red Raider Region mission and complete it. The Forbidden Planet mission will likely start concurrently with your efforts, and you should attempt to resolve this peacefully if you wish to keep the Ermyr Defenders as trade partners.
 
Considering the above, you should have a trade location mapped out via a new Gateway, and with it an asteroid field to exploit for minerals.
The staff at Celaeno Station should periodically suggest new Gateways found by their research efforts. They should be a priority for you to explore.
If a region turns out to be too risky to traverse, feel free to return to the previous regions of Unknown Space and grind until you've outfitted your ship with more suitable engines, weapons, armor, etc.
Subsequent missions will introduce you to the game's major antagonist faction, along with re-uniting a missing Starcom ship with your faction.
In your exploration, if you are suggested to take on optional missions, they may be easier resource rewards than grinding
The remainder of the game involves the careful negotiation of the rest of the galaxy in order to research enough technology for your ship to travel about with impunity, and to determine a way to return to Starcom space. Interactions with new alien factions and maximizing the potential of your command crew will be essential.
The history of the galaxy will form a necessary background to your investigations, as well as guiding your decisions.
If you need assistance with a specific mission, you can look it up in the Missions category list.