My gallery here is much more of a test environment/play area for an on going development of 3d skills based in a cheap 3d app, mostly geared at 'realism' (not an end in itself rather than a benchmark learning strategy).
It might be more useful for me to comment on how I developed core skills as a painter, as I think it transfers quite nicely across the range of artistic disciplines.

I learned about image making over the years largely through close observation and comparison of various artistic 'styles' and approaches - by physically re-creating them.
Way back when I was still in school I was copying & recreating elements from images made by my favourite fantasy artists (Vallejo, Ian Miller,Tim White). Later in art school I pretty much did the same, but now with the old and modern masters (Titian, Vermeer, Seurat, Richter). I've continued that approach into my professional career as a painter/illustrator/artworker.
Just as a reference, one of my latest renders here was a partial recreation in Poser of a painting by Gerhardt Richter called 'Betty' - I called mine, appropriately, 'After Betty'. Google the painting and compare with my render and you'll see the influence.

I think the thing that's really important about this approach (studying through recreating) is that you investigate what other artists were trying to convey and how they did it in the most direct way - not only reading about it and looking at the images, but re-making them. In this way you begin to build up a visual dialogue between yourself and other artists, and a vocabulary of technical and emotional devices. You can closely compare your work with an original and make critical decisions about what is and isn't working. Its a way for the artist to empower themselves rather than just relying on the critique of others, which can often be riddled with individual bias that isn't necessarily useful in terms of what is trying to be achieved. Some critique is very useful though - don't isolate yourself.
The knowledge gradually gleened from this approach is invaluable IMO in moving forward to create individual, original works. It's kind of how I see art as having developed over the centuries.

I'm not going to attempt to critique any of your renders, but my advice would be:

1. Assess from the start what you are attempting to achieve with your ideas and your technical approach.
2. Look for other artists from a variety of disciplines  who have similar concerns, study and even recreate them either partially or fully.
3. Observe and compare, Observe and compare - don't accept the details that are technically bugging you (stretched textures, shadow artifacts, bad lighting and shaders) - they will leap out of the image and destroy the illusions you are trying to create.
4. Be persistent, and take the time - I'd rather a single image take me a month to produce and be powrful and excellent than churn out dozens of images that fail at every level. Some ideas can be treated with less concern for technical detail, but they still require an approach that conveys their message effectively.

 

PoserPro2014(Sr4), Win7 x64, display units set to inches.

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