Some important things No Man's Sky doesn't really make clear that are important:
1. You can only have one Multi-Tool. I wouldn't prioritize spending the credits you need for a really good one until you have found and hoarded 3 S class scanner modules like Kanil suggested. And when you've done that, you'll then want a Multi-Tool with enough slots to fit all the mods you want. But you may be offered one for free in NPC conversation at times, so just be aware that you can't get the old one or any existing mods/tech once you've switched.
2. You can only own 6 ships (the ones you actually fly--fighters, explorers, haulers, and shuttles) at a time. These will stack up quickly once you start finding crashed ships. Once you're at the limit, the last ship you hopped into the cockpit of becomes the ship you'll trade in during any future ship transaction--and since that's likely to be the ship you tool around in the most, full of all your stuff, be careful. Use the Summon Other Ship command to call and hop into the cockpit of the ship you actually want to replace. Make sure you keep the launch thrusters of your backlog of ships topped off to enable this summoning.
3. Freighters are like the Multi-Tool in that you can only ever have one. I'd suggest following Kanil's advice above about only rescuing a Freighter you like the look of early on (you'll keep getting opportunities).
Part of the fun for me has been figuring everything out, so I won't overload you with info
@NewlyRetired. But I'd be lying if I said that the NMS reddit and google haven't been an essential part of me avoiding too much frustration so far, so if you want more info let us know.
I agree that you should always just do what you want and explore any planet/system at your leisure as long as you can survive it. That's part of the fun. But I would just advise that it isn't really necessary to find everything that a world has to offer or strip-mine it really. As soon as you find yourself wanting something new, go. Other than specific quest markers there's nothing you HAVE to be anywhere in particular to do. Personally I hop around quite a bit and really only priorotize Drop Pods and crashed ships on planets. I haven't needed to grind for money since I tricked out my new Multi-Tool with S tier scanner mods.
I would follow the main quest for a bit to get your feet wet and teach you how to craft some important stuff--the game autosaves when you get out of your ship and it manual saves at save posts you'll see in certain areas--but you don't want to only rely on a single autosave slot that rewrites. Learn to craft a save point early and keep it on you--you can pop it on the ground, save manually, and pick it back up immediately. Painless. Always remember to pick up your portable equipment. Can't count how many Signal Boosters I've accidentally left behind to the wilds when I only ever needed to craft and keep the same one from the start.
Oh, and you'll be able to change your appearance at space stations.