Something I've told a few people trying to get into concept art lately:
Your portfolio has to show that you understand exactly what the job is!

Unfortunately, lots of what industry folks make on their down time is specifically not what they do *at* work, but *away* from it

This is also true of a lot of popular insta\\twitch artists. They are making good art! but they aren't making *concept art*. They aren't working as part of a team- so making art like theirs, as a beginner, will give you an uphill employment-seeking battle.

You need sizzle in your portfolio for sure, but it needs to have a healthy dose of production minded work that shows you know that concept art is about working with design\\3d artists to work within restrictions! This chocobo image is 20% of the job if lucky. This crate is 80%.

There's always gonna be exceptions to this advice- but I would personally rather hire someone who clearly was used to drawing within set boundaries in a production-minded way than someone who only had blue-sky, epic illustrations, esp if they had no real prior experience!

Things you should have in a beginner concept portfolio
-prop designs + turnarounds + material callouts
-character skins + turnarounds
-VFX concepts (trails, poofs, magic spells)
-Facade designs, door\\window designs
-Drawing over 3d blockouts of levels

But don't just use this list- RESEARCH. Look at production work on released games! Learn about how 3d artists work for efficiency! (learn 3d even!) Work on mods if you can, or pair with a 3d modeller at your same level and make work together.

and again, I'm SURE you will run into people who didn't do any of this and got jobs just fine. Great for them!! But if you don't like doing this stuff for your portfolio, you probably won't like doing it all day long either :p

eat those veggies, kids

Oh, and guns. I hate to say it, but if you want to work in games, having guns in your portfolio is honestly kind of useful. A lot of work out there just wants you to draw a bunch of guns. You don't have to, but if you don't have an aversion to it, it's a good-to-have.

They can be goofy guns, tbh. Don't have to go all second amendment, but the experience of designing even a whimsical gun both from side and first-person view is a good thing to have.