What add-ons, competitions, and helpful websites would you recommend? Where should I get my textures? What add-ons are best for speeding up modeling, shading, sculpting, etc? Would you recommend Pro Lighting Skies or Studio? What contests should I enter to improve my work?
Hello William, I wrote an article a while back that discusses some of our favorite resources online here: Our Favorite Resources. I can't speak on addons, maybe others can chime in on that. Ditto for Pro Lighting and Studio.
Regarding contests, I don't think you need to participate in contests to improve your work. We do have a number of exercises you can use to challenge yourself, but ultimately the best way to improve your work is to set goals for what you want to create and start slowly chipping away at it. Build something daily until you feel completely confident in your skills.
For reference images I think it's highly subjective to what you're looking for. If you're looking for general blueprints of objects this place was one I used a long time ago: https://www.the-blueprints.com/ some of them can be hit or miss depending on how popular they are. I've seen some really intricate and detailed blueprints including some that have vector versions. Hope that helps.
What are the pros and cons of using substance painter/designer vs photographed textures? Are there programs similar to substance? If so, which one should I use?
It comes down to what you are using them for. with photographed textures you will also need normal/roughness/metalness channels for blender, that might not always come with the just photographed texture and you might need to make those yourself.
With substance painter/designer you essentially create what you need similar what you can do inside blender using procedural textures, and you get all the textures maps you need.
similar programs, quixel suite and blender. and it comes down to what you need. personally the stuff i do i've found blender and substance to be best for me, i like quixel aswell and you can do amazing things with it.
You can't really compare the two really. Substance Painter/Designer are programs for texturing and you can use photographs as textures in those programs as well and people often do. I personally only use Substance Painter for texturing as I find it to be incredibly robust and efficient at texturing.
There are a number of programs out there including Photoshop, which I know a lot of people still use, but Substance Painter is by far my favorite and I stick with that. I think it just comes down to your personal preference. I don't know of anyone that has used Substance Painter/Designer and did not like it. I would recommend trying it out.