On this wallpaper you have a really good concept, actually wallpaper looks really good in this small resolution... but I went to your DA page to see bigger image and get the conclusion that you have a trouble with the quality in high resolution.
Ok, here is the basic stuff (maybe some of the options you already know):
- using of layer mask can bring to you more control on effects you use... for example, your player image have strange colors in some parts of the body... to neutralize the color, first Duplicate the layer and then do desaturation (hue/saturation option, put saturation arrow to the left). Then make layer mask on newly created layer. If you know that with using black color in Layer Mask you can delete certain parts of that layer, and white brings that layer back again, then it is logical what you need to do. Try to use Brush tool (use soft brush) with black color and try to 'paint' on layer mask. How Layer mask works check out here: http://www.wpgallery.com/eng/goodies/tricks/mask.php
- explanation is with using Gradient tool on mask but try it with Brush tool... have in mind that if you use 30% of black in layer mask, that part of a layer will be 30% transparent
what Layer Mask brings? More control of filters, effects, layer control
- finding a high quality renders or photos can make your life easier (you always use low quality photos). In other hand, if your photos are quality then you're changing size several times and it looses quality, or you're saving with low quality jpg settings.
- anyway, if you're want to improve image quality (and I see that you can't wait to do it
) then remember, patience is everything. you can find several solutions... to manually achieve photo-retouching, or to find a good filters like TOPAZ filters are (which you still have to control) / for photo-retouching you need lots of practice and it really really helps if you have TABLET (graphic table)
one thing have in mind, you have a good potential and nice ideas, so keep practice, learn from suggestions and I think believe you can make quality of your works on higher level