I'm trying for realism

It would be a pleasure to get tips
OK, to start, your composition might be one problem. You have centered the focal point, and generally that makes for a duller composition. If the arch opening is your focal point, you may want to move it up/down or more to one side or all of that. Look up "rule of thirds" for example as one compositional choice many people make.
Second, it appears that your drawing is from your head, an idea of what a stone or brick structure looks like, rather than the more likely shape and size of the bricks/stones. Same for the water. I have no idea what you're trying to do with the sky nor your foreground foliage.
I'd suggest that you try learning to draw this from a photograph. Copying more what you see, than what you think things look like.
To be honest, what may be baffling you most is how to draw realistically. If realism is what you seek, then work on drawing skills first without adding the complexity of painting skills. That's the way most folks do learn, in my experience.
For realism it is not truly that important that you get everything "right" or detailed or exactly like life. You can suggest all that once you learn the basics of drawing.
Another suggestion is to view a lot of "successful" paintings of your subject. For example, you could use your browser or a pictorial program like Pinterest and use the prompt "stone bridge painting." You'll see how others achieved what you seek. Copy those to learn. In time your work will improve. You'll get something like this:
Stone Arch Bridge Painting on Google or this:
From Pinterest
As to satisfaction, much of the time even with great skills and experience you'll discover artists are critical of their own work. Doesn't matter.