Looking for advice on Freelancing

Have you looked at Artstation?  The job opportunities are geared heavily toward games, but if you're looking for concept work, that could work, too.  There are plenty of artists that don't do games on there, and it's a really professional platform for a portfolio and to connect artists to clients.

If you want to sell assets on a store, there's plenty of stores out there (Blender Market, Unity Store, Unreal Marketplace, etc.)  Search for it, and make sure to read the terms and conditions.  When I looked into it, most websites said the art you put on there is still yours, you retain all your rights over the work.  Most of them also give you 70% of the profits, too, which is pretty damn decent.

For portfolio tips, begin and end with your strongest pieces.  You get someone hooked in the beginning, and you want to leave them with a strong impression at the end.  Also, alternate better pieces with less strong pieces to keep a consistent level of work to the entirety of your portfolio.  I swear there was a video talking about portfolios under the Concept Art section, but that must've gotten lost in the shuffle.  I thought that was useful.  Too bad it's no longer available.

I'm terrible at networking, at least with the keeping up with people part of it.  I guess just check in consistently, keep those ties going.

Don't be discouraged at first if you don't get a lot of work.  It takes time to build up your reputation and client base.  Just keep at it, and eventually you'll get all the work you can handle lol.

If you have any more questions, feel free to ask.

Basically everything that was mentioned before I agree with. I believe you have experience working with Unity so I would create an account on Unity Connect https://connect.unity.com/ it's kind of like Upwork but for Unity developers. They have a job section as well so you can browse through it and setup a profile and even post projects you're working on. 

Also I would recommend keeping a LinkedIn profile active. I've had one for as long as I can remember and from time to time I get job offers through there for various work some of which I have gone through with. It's easy to keep active and it's a great way to have an online resume of your work through LinkedIn. 

I am really having trouble getting into the freelance world. I've been trying a lot on Upwork, Polycount, ArtStation and a couple other places, but have pretty much gotten nothing. Since I don't know anyone in the CG world or have any relevant connections, I'm not sure what to do besides post my work online wherever possible. I suppose I can just keep building my portfolio since it's not very big yet, but I don't know how else I can go about finding freelance work. Any suggestions? Here's my portfolio for reference https://mcurt09.artstation.com/

beautiful response, thank you!

I had my attempts at freelance pretty disheartening to say the least.

Now to mention I am a full-time employed outside of creative industry so it is not a question of survival but rather self-realisation. 

I had some small portfolio but I wasn't really aiming for top class production opportunities - just the ones that look like small/pet personal projects in need of help for small payment or even free. Because I thought when money's involved that would drive motivation and responsibility from both sides.

But man...people expectations are so high on this stuff. It's like people would like Pixar or J. Scott Campbell quality stuff for their lunch money and nothing less.

I ended up landing nothing on Upwork or Freelancer.com. 

One guy was active enough even to reach out and tell me not to waste time there with my level of skill. Like he was nice with words but pretty harsh with the meaning leaving me completly destroyed for a few days.

The lesson I got for myself is just to 'git gud'... Like go on doing stuff aiming for being awesome and something would come up eventually. 

Your portfolio is quite small. While I can tell you have skill, it's tough to really see what range you have. Pretty much every piece is stylistic, so if I was someone that was looking for a realistic modeler I wouldn't see this portfolio and think you were the right fit. I hope I don't come off harsh.

 I would first ask what you're looking to get work in. What would your ideal project be? That should be shown through your portfolio. If you do indeed want to work on more stylistic types of work then continue adding more to your portfolio.

 If I were looking for someone who created models with your style I'd like to see a wide variety of content that shows what you're capable of. Having a small portfolio greatly diminishes that. To add to that, look at the style of work being produced by the companies you'd like to work for. Try to replicate that kind of work in your portfolio. It's much easier to sway someone (or a company) to hire you if they feel your style closely resembles past work they've done. 

That's the conclusion I feel like I am slowly coming to, unfortunately. I would still like to vet a few sites and see if I can get a hold of something that works for me, but Artists in general are massively undervalued.