You have some interesting and appealing stuff. But some of the subjects you're shooting are pretty heavily covered already. Flowers are in demand but you're competing against a gazillion other flowers so yours may get lost.

I'd suggest doing some research into what subjects are in demand and seeing what gaps you can fill.

I think if you are going to shoot flowers and skies maybe brighten up the mood a little. Try some sunny happy skies instead of storms. I don't shoot flowers but I'm guessing that most of the images are used in positive light. Personally I like storms  but probably a tougher sell for stock. I haven't had much luck with somber skies.  Also, taking some of the black out of the images might help also, hard to say. Very nice images though!! Keep experimenting and you will find something that works better for stock. Just my own personal opinion.

Having many more images will also help quite a bit.

you're in my old home-province of alberta. so you're within travelling to the rockies where there are lots of different more sellable subjects to take photographs of.
pauliewalnuts is right, your portfolio is a well covered subject, and unless it's something unusual, it can be lost in the gazillion of photos .
try looking for other uncommon but sellable subjects. as i said, you are in an excellent province . if you have a car, you should not have problem finding the right subject within a day's drive. good luck.