ok good. well your doing the right things... levels, s-shape curves etc, so theres no problem there. What i tend to do is after i have applied a curves layer, switch it on and off... see if there's too much contrast... maybe even adjust the opacity... its better to build up curves layers rather than try to get it to do everything in one layer... so you may need a second curves adjustment to brighten it more.
After making your adjustment to the image as a whole, then its time to look at zones.
So for the forground i made another curves layer (always use the curves option at the bottom of the layers pallet) and made a bend nearer the lower end... this controls mainly the shadows and as the forground was so dark i wanted to brighten it a little..... so dont worry at this stage about the rest of the image, just brighten the forground but again not too much.. its all about subtlety.
Once it looks brighter in that area it time to use the layer mask. If you made your curves layer using the button at the bottom of the layers pallet you will notice that your curves layer automatically has a layer mask attached... here is what it looks like (taken from another image i edited)....
Now you may want to google or youtube some layer mask tutorials but basically the golden rule to remember is Black - (takes away) white + (adds) so when you paint over your image with black or white brushes it takes away or re-applies the curves layer you just made.
It takes time to get use to... play around with it... once you master layer masks your editing capabilities will dramatically improve.
For information; you can add a layer mask to any layer by clicking the layer mask button on the bottom of the layers pallet... so if you wanted you could duplicate the background layer, mess with it, change the colour for example, add a layer mask and then remove parts of it so the one beneath shows through.
There's quite alot to take in at first.. so play around with that.. layer maks are always included in not only curves layers but also levels, hue/sat etc so it can be very useful if one part of the image looks great with an alteration but it messes up the rest of it.
Next is slightly more advanced (and confusing) but i will briefly explain it anyway...
I duplicated the background layer set the layer style to screen, reduced the opacity and then layer masked it so just part of the forground was effected... this again brightened the forground and can be useful if it needs a boost.
In the end i had around 4-5 curves layers, all on different zones, the levels layer, and also a colour curves layer (which i wont go into but it works like colour balance)... i then flattened the image.
Then i did the dodge and burn proccess... which again, the way i do it very complex but you can achieve similar results using the burn/dodge tools... just remember when you start, to set the burn to shadows only... dodge to highlights only... and BOTH only on around 4%...this is the easiest way to use these tools for the first time.
Burn all the shadows in the bottom of the forground and dodge a bit of the clouds and in this case the guys T-Shirt to make him stand out.
I finished by sharpening with smart sharpen... unsharp mask will also do...
I hope this helped.. its hard for me to explain some things as i tend to just do them after using PS for so long... if you want to find out more, look for video tutorials on the web, mainly for..
-Layer masks
-masking
-dodge and burn
