Not rubbish mate! What you are trying to achieve is fine and it's only practice and repetition that will give you realistic results.
I give myself a little training even when I'm out driving the car in the countryside or by the sea. I tend to look at a view the count how many different varieties of Green I might see and how they are positioned separately or blend together.
Another time I might check for Blues or Browns. So, I have found this useful when choosing colours in Surveyor.
When colouring trackside mountain cliffs or cuttings with rock formations that appear prominent among the general ground-cover, I look for something that will give contrast but will blend with the surrounds. I usually add these into curves in the track to make for better screenshots. Along these areas, I never widen the 'Radius' over the 9 O'clock point and generally a little less. I vary the 'Direction' according to the way I want the rock formation to run and at the same time, modify slightly the 'Scale' ,.. the closer to 'O' the sharper and smaller it is,...further away it's blurrier and larger,... AND I never paint it on like a spray-gun. For the detailed areas I only use left-click mouse one shot at a time. I always mix the 'Scale' because you rarely see identical rock formations, unless it's a tessellated region.
My suggestions: Your general landscape is fine, earth colours are fine, add random rock formations that are different to your ground cover on either side of your track; increase the spline points of your track (+1) and bring the earth up to meet it creating a slight ditch on either side, you may need a little more ballast. Pick out a grass spline maybe a JVC#(GR1) or a dry variety to run along your ditch. Darken your ditch colour and this will give greater depth to your image.
A TIP: One colour that you can use to fill in around scattered tree areas is 'FFR Dirt & Leaves 01' - You'll be amazed at how you can use this one colour to splash around shrubs, trees, off-road parking, etc. It just gives a more natural look to your scenery.
No doubt there will be others who will give you much better guidance than I.
Cheers,
Roy