Hi Natalie!
Lots of discussions here, search past one for fantastic ideas.
Some quickies:
1. Fill out the description for every image. Tell about it. What's it's story? When, where, why, whatever info fits the painting.
2. Tell what medium; "painting" is not the medium. Was it acrylic? Oils? Colored pencil? Markers? Shoe polish?
3. Post only appropriately photographed or scanned images. Please don't be offended, but this screams hobbyist/amateur:
I actually like this painting, but the presentation turned me off. And the description "beautiful painting for sale" tells me nothing. I'm curious as to where it was, what kind of flowers, is it from your imagination, why did it move you enough to paint it, what came from your heart when you painted it... see what I mean?? By the way, I love the title you gave it.
4. Daffs in the Valley was shown sitting on a pair of jeans?! Visit other artists pages, and see the professional way they are displayed. There are many free editing programs that will let you crop out the background, adjust for lighting, etc. I use Photoshop Elements, but others have mentioned GIMP. Others will probably have more suggestions on that. Just doing that alone, plus giving more information, will improve your first impression by a thousand percent.
5. After you are READY for customers, then the next thing is the hard work of marketing. Promote on social media, etc etc etc etc.... Lots of ideas here in the discussions, so won't repeat them. Oh, and find someone successful, and see what they do. Then you do it, too! A couple off the top my head: Mike Savad, and Sharon Cummings. Top sellers here. Must be doing something right, yes?!
My best to you!