Is there any way to increase your vision naturally without contacts, etc?

No. Unfortunately there is no homeopathic, natural or other method to change the refractive error of one's eyes besides spectacle / contact lens correction and refractive surgery. Anyone who tells you differently is trying to sell you something. It would be a great and revolutionary discovery, but it simply is not possible.
Hard question. I don't think there is a "proven" way to "increase" one's vision. I have heard and read about methods that their investors claim to work to improve vision without use of eyewear, but I can tell you that if there was one according to them, it would just be so rigorous that it's almost next to impossible to follow it.