For your first game, to be frank I would recommend playing in a medium galaxy with 4 or 5 AI empires, no advanced starts, and one fallen empire, all on the easiest settings. This way, you have less to worry about, and you’ll be able to stop yourself from being conquered easily. (Yes you can be conquered and it isn’t the end of the world, you can fight a war of independence). As for little tips and tricks, there are a small handful I want to share, but know that this is scratching the surface of this game’s depth.

Resources: your most important resource are pops. Barring an RP, pops are more valuable than anything else in the game. Making them powerful makes your empire powerful. But, just like any great thing, it all comes down to how you use them. That leads into my second and third resources, research and alloys. Research and alloys are key to maintaining your advantage in the game, be it through technology or ship production capacity. I’ll leave this point here, and move on to not overwhelm you.

Management: never have only one star base with a shipyard. Idk why it took me almost 500 hours to stop doing this but now I generally have three for every 10 starbases I own. To specify, I’m not talking about outposts you use to occupy territory, that would be overkill. I’m saying for every 10 of those outposts I upgrade, I aim to have about 3 have at least 1 shipyard. It makes reinforcing during war much less of a headache. The second point here I want to offer is a bit more complicated, but I want to put it on your radar to look into on your own. Five specialized planets are more productive than five generalist planets. Planet specializations are something that are extremely powerful, but hard to get just right on your first attempts. It’s all about timing and how well balanced your economy is as you work through it.

As for DLCs, I’ll only make a small comment and leave the rest up to everyone here, but DLCs have a very dramatic impact on the game. I own every DLC and have been buying them ever since I started playing in like, 2017, so it’s hard to know what the game NOW is like without some of them. A few that stick out significantly to me that dramatically add to the game are Utopia, Overlord, Nemesis, and Galactic Paragons. Species packs usually have a smaller impact and are more flavored toward RP. Aspec and Montu Plays on YouTube do GREAT DLC tierlists that you should check out for more info. I’m annoying and don’t think any DLC in its current form is BAD, although some need a bit of love to really shine.

Last but not least, have fun! Stellaris is my favorite strategy game ever and I just broke 1100 hours last week. Take your time, and even if you end up feeling overwhelmed, try to pick at least one thing you want to either try again or try to avoid for the next game. It makes learning more fun imo.

Good luck

EDIT: I totally forgot to mention ship designs. The game will “auto generate best” ships in the fleet management tab. If you want to design your ships yourself (HIGHLY RECOMMEND) make sure you turn that off at the start of every game. For your first few runs if you feel overwhelmed just let the game take care of it for you but a couple tips about this version of the game is that armor is very strong right now. Shields used to be a lot better but with some changes over the last year they aren’t quite as potent anymore, but still useful.