I would just like to point out that tbc started the thread for critiques.

Not everyone is right and some critiques could be against what your ideas are. Take out what you think is good, ignore the bad and learn from others' opinions.

It will only make you a stronger artist

So, anyone: Where did I go wrong with this? The transparency in the brushes?

The transparency of the brushes, definitely, but also the blurring of the background seems unnatural to me, and (this could just be my tastes), it BEGS for something big, and focused in the middle.  The trees are pulling my eyes to the center of the canvas; the hawk is too high for that focus to be satisfied.  Perhaps a huge setting sun at the horizon line (of course, then you would have to do more with the sky).

First mistake...mirrored trees.....another common fault with copy/paste.

No two trees will be alike, and your audience won't be tricked by/with mirrors.

The grass/ground has no substance...unless the intent is to represent trees growing on grassy [ish] clouds...

The trees are brushes, but yes I did use the same brush on each side adding more to the left side. I was attempting to create the ground cover with only brushes and texture but I grab from what you are saying that I went too soft with it. I was going for dreamy but I guess the whole image is too soft. Did I interpret correctly?

I think if you're going to go dreamy, then everything needs to be soft.  The hawk is super sharp, so the dreamy effect comes off looking a little dirty.

There's the fundamental issue with 'brushes', as with all image generators.

Traditional 'art' would see a 'brush' as a stick-with-hair-attached - used to apply individual strokes from personal, human input/creativity.  There can be NO repetition of 'pasted' images without deliberate intent.

If you 'paint' each tree as you would in non-digital imagery....by hand....then there's no danger of repetitive images....

I'm not having much success "Painting" with this damn mouse!

'Painting' can be done with a mouse...as unlike 'normal' artforms digital 'art' has the option to zoom in on detail.

It is not uncommon for skinners [in particular] to deal with images at an INDIVIDUAL per-pixel level.

This is what often differentiates skilled creativity from 'filter frenzies'....the latter is typified by what was/is commonly refered to as 'blue swirlies' - one of the no-no's of wallpapering....

Frankie...the grass/ground looks cloned... the brush or cloning looks artificial because there are no 'identical' plants (like trees).

I have been trying to rework this image. If it's a waste of time, please let me know or if anyone has some useful advice, it would be welcome.

That is a big improvement!

There seems to be something not quite right about the clouds. If you are going for a foggy look, maybe make the clouds less "puffy" looking, more hazy...and the farther you look into the distance, the less you should see.

If it's a partly cloudy day, I would suggest geting the clouds off the water and giving them more depth, maybe with more layers of them and more light and dark parts of them....if that makes any sense.

Actually, at the moment all I have are rendered clouds as I was spending so much time on it, I wanted to know if it had potential before I did anymore. I was thinking to blur the water line and add more clouds. As I said, right now it is just rendered clouds with a gradiant mask. I learned quite a bit about using masks in some tutorials yesterday while my system was down and I was using the "ancient one" which   won't run photoshop so it forced me to stop trying to create and try and learn something!

I think it's worth persuing.

Grass in the middle is flat...2D....the bit to the right side is better.

The clouds between the viewer and the water look more like smoke.

The 'grass' "brush" is still evident..... identical bits of grass....rather unlikely.