What is the best way to learn 3D Low-Poly/Geometric character and asset creation for Unity?

Hello, I want to learn how to create low poly/geometric assets to use in my game. Nothing super complicated, just stuff like this
:
I can make very basic things in Blender, but I am open to using any program. I really like this game style and I hope to evolve from it eventually into more detailed modeling. Please refer me to some tutorials! Thank you.

 

You could start by learning from the dude who made that orc you posted-
https://www.youtube.com/user/pigartt/videos

and this one, really good stuff as well-
https://www.youtube.com/user/MuchBadSS/videos

 

Blender can do anything any other program can do and then some, for the most part. It doesn't matter which program you use - Blender is fine.

Pigart really doesn't do tutorials at all, last I knew, but you can certainly learn alot about low-poly by just watching his work, as linked by tomventom above.

For a really good, thorough low poly asset video, check out this one:

It's one I really liked when I was trying to figure things out. It covers pretty much everything involved in a basic piece. Mind you, he is only make a street sign in it. I don't know if he has any other good ones on his channel, but you could check for others. I think he has some character modelling videos, but I don't know how low-poly or well-explained they are.

Maybe more useful to you would be the Blender character series by Sebastian Lague(he's something of a tutorial making celebrity on these forums). His series may be perfect for you. He makes a low-poly character, textures it, rigs it, and even animates it.

https://www.youtube.com/playlist?list=PLFt_AvWsXl0fEx02iXR8uhDsVGhmM9Pse