My first piece of advice: do not loot everything. It feels wrong not to, but most of the loot you see laying around is junk not worth much, and is just a waste of time. Look for stuff that says it is used in crafting, or weapons and spacesuits(which sell for alot), plus healing items and ammo.
To get your companion to fire weapons, give them a weapon and a single round of ammo for that weapon. They do not use up ammo, so they only need one round. This also means that the best weapons to give them are ones with a high rate of fire.
Mission terminals are godly. There is one right in
New Atlantis, not far from where you will be going anyway. Speaking of New Atlantis, the Tapping the Grid mission can be incredibly annoying. Remember to activate the scanner so it can show you the path to take to save a whole lot of frustration.
Perks to get early(bolded are must have early to my mind): Weightlifting(carry capacity), Commerce(sell for me, buy for less),
Persuasion(better chance at persuasion checks), Ballistics(better damage with most weapons), Pistol Certification(better damage pistols),
Medicine(more healing from med kits, oh so important),
Boost Pack Training(cannot use boost packs till you get this, so should be an absolute highest priority), Piloting(allows you to use boost in your ship, which among other things can break missile lock),
Security(allows you to pick higher level locks and makes it a bit easier, get right after Boost Pack Training), Targeting Control System(allows you to target ship parts, meaning you can disable and board enemy ships). There are a ton more useful perks, but these will get you started, edit: Add Stealth as it gives you a bar showing if you are hidden or seen.
Fast travel: open the mission list("L" on PC), hover mouse over mission you want to travel to, hit "R". Speeds up the game alot over doing it manually.
Cargo hold access in ships is right behind the pilot chair in every ship I have seen so far. Embarrassing how long it took me to figure that out. Look for the green lit panel.
If you are expecting a huge step forward for CRPGs, you are going to be disappointed. It is largely Fallout 4 in space, with great graphics and maybe the most ever to do in a Bethesda game, but nothing particularly new. It is well done but not innovative. I like it, alot, but many people won't because it is stuff we have seen before. If is Fallout 4 plus No Mans Sky plus a few others. It is not new, it is just good.
