[quote=Touch of Insanity]
I guess I should post something. I've been working on this for almost two years because I keep getting angry and quitting. Only to come back of course a few months later.It based off this picture 
[/quote]

I think I remember you posting this back on OldGuild.

[hider=paintover] [img]http://i.imgur.com/qtXd3yF.jpg[/img] [/hider]

1.) You're having issues with your values. If you flip the drawing to black and white it's easy to see that you haven't got a focal point because you're values are currently too uniform. When doing paintings a good rule of thumb is remembering things in terms of 'foreground, middle ground, and background'. In general, objects in the foreground tend to be darker in value (because they're right up close to you and you can see them the best, so they'll have the most contrast), your middle ground has mostly mid tones, and then things in the background generally fade or get a bit lighter because of something called 'atmospheric perspective'. (Basically, that's when dust and water particles get trapped in the air and partially obscure things getting further away -- the farther they are, the more they fade because they have more 'atmosphere' between your foreground and their placement in the background.)

Now, if I take and darken down your foreground (the figures, obviously, and the chair they're seated on), then lighten things heading off into the background a bit, you can see how it starts to make your focal point (the figures) more pronounced. When trying to imply lighting, values (your lightest lights, your darkest darks) are wicked important -- colors are really only a small fraction of the battle, your values are what will make things believable because using them correctly is what will give all the objects in your painting their proper forms. For instance, look at the original painting and look where the two women are leaning against each other. Now look at it in grayscale. You'll notice that the sliver of blue between the bodies that you used to try and imply some of the background showing through is basically the same value as the arms of the women themselves. This causes a muddled/muddy feeling visually because your eye is looking for a value change to help separate everything out. Once I put the value between them lighter, see how it rounds the arms out a bit more, so you can see the two women are separate objects and that shadow is currently darkening their arms down? The same goes for the woman on the right's dark bikini -- it's the same value as the pier/land in the background, so the two fight each other for attention, even though they're different colors.

Values, values, values. They'll make or break [i]any[/i] piece.

2.) Now, I touched briefly on colors being of secondary importance to their actual values, and that is true, but colors are still important. (Obviously.) For this piece, your light source is the sun (warm), so your shadows are going to be correspondingly cooler. (And the reverse is true in other scenarios where the light source is cool, then the shadows will seem warmer by comparison.) Do you know why the shadows under the chair are purple/blue? Because they're receiving ambient bounce light from the sky. Wherever the warm sun color can't reach, the rest of the sky will light it as a secondary cooler color. (You'll see this a lot on a sunny day if you look around outside. Shadows take on a very blue tone.) Now, you did pick that up from the original reference picture, which is great, but you forgot to add that cooler color back into the shadows on the skin. 

Check out the swatches I color picked -- yours on the left, the photo's on the right. Notice how much warmer all your colors are than the actual photo colors? It's perfectly fine if you want to exaggerate some of that warmth to help sell the beachy/sunny day, but remember to cool down your shadows, too! Add some of that ambient blue/purple back in to help your figures feel like they're actually a part of the environment they're placed in. (Everything in the picture has to have the same lighting/color rules apply to it, if you want to have it feel like it's all existing in the same environment!) 

3.) Anatomy. It's the bane of every artist, and rightfully so -- it's very difficult, but extremely important. The way these two figures are currently rendered, it looks like you seriously need to work your anatomical knowledge. Knowing where muscles start and end, how they wrap over certain bones and such, that'll help you to know how to render your figures correctly. For instance, the leg that's crossed over the other on the redhead's figure -- you've implied (I'm sure unwittingly) that the thigh to the knee is bent/curved. The bones in that area prevent the upper leg from moving at all -- you only get movement at the joints between bones. And, as you know, the bone in that area of the leg is straight. Any movement we're getting there is the muscles and fat being displaced as the other solid leg underneath pushes it, resting the top leg comfortably above it. If you look at the photo, you can see the thigh muscle there is straight where you've drawn it curved. You drew what you [i]thought[/i] you saw, not what you [i]actually[/i] saw. Doing anatomy studies will help you to correctly map out your figures, both from reference photos and, eventually, from your own imagination. They're not always fun to do, but they'll eventually make your drawings more solid and, inevitably, easier to bang out.

If this were my piece, I'd be harsh on myself and scrap it. You can't be afraid to kill your darlings. (As I've had it said to me by mentors on many occasions when I've done pieces that needed revisions.) Sometimes it's just best to start again and try to correct errors from the ground up -- the more you render on a piece that has issues, the less and less you'll ultimately become happy with it. (Because you can only hide so much with rendering.) If you do decide to start again, keep the critiques in mind, use your original painting to reference your changes, and see if you can improve on what you had already done. (Keep the things that work, get rid of those that don't, etc.) It will very likely go faster the second time around and you'll probably be much happier with it.