You could post your art, or whatever you believe is interesting. From my experience, rants get the most views and comments, if you're willing to go there.

Rants always do. People who agree will like it, and people who disagree will most likely present rebuttals in the comments. Plus, the fact that most rants contain little to no well-thought arguments makes them a prime target for people who do discuss by using proper arguments. (However, this does not mean all rants are poorly thought out, poorly argumented ones.)

On topic now. You could indeed practice digital art and post some stuff you made every now and then in a blog here on the forums. That way, you'll likely attract people who will give you constructive criticism. Maybe try posting it in the Art section of the forums as well.