First, it helps if you understand the terms and technical aspects of an image. If you understand color, saturation, contrast, levels, black and white points and curves - it helps a great deal. Let's see if the MM community can expand on this.

The reason most people ask the question "how do I get this look?" - is that they are not aware of what characteristics make that image.

The first thing about images is to start with a average "standard" image. Kodak defined it as a picture with 25% shadows, 25% highlights and 50% midtones. We assume the image has a true black (D-max, or maximum density) and a true white (100% of R, G and B). That's additive color, lets leave out subtractive color for a while.

Vivid, bright, vibrant or colorful are terms some people, rightly or wrongly use for saturated pure colors. Muted, soft, muddy are some terms use for desaturated colors. Right or wrong, these are relatively imprecise terms.

Lets explore the different aspects of an image that creates the "look".

We could post some before/after examples as well as samples of different styles. Emphasis maybe on why it's done and not just "how".

Reserved - standard image, what it looks like in levels, curves, contrast, saturation etc.

Reserved - levels, contrast, black/white, highlight/shadow

Reserved - color

I am noticing that there are also "STYLES of Looks" too. 

It used to be that we tried to shoot technically perfect skin tones... as one main "Style" and "Look" a time ago.  Not so today anymore.  The Look has gone from perfect skin and accurate colors to an artistic, moody, trendy set of colors...in some cases.

At some point "We All Got Bored" it seems with perfect skin glamour images... with perfect whites... and perfect blacks and totally accurate colors!  Beautiful and accurate... but BORING... after seeing it so much... for so long.   So... especially in trendy magazines... who are known for doing things different...to keep fashion sales moving...we began to see images where the "Look" was anything but perfect!  The perfect skin tones began showing up as dark... and even looking like magenta or brownish toned skin... anything but perfect...especially in trendsetting magazines like Vogue for example. 

In magazines today, if you want to be considered an artistic or trendy photographer... your pure whites should be pushed to look yellow toned... and the darks should look blueish or some other color tone. And there are sometimes hazes or color casts thrown over all the image for art's sake.  Anything but purely real!!!  Thats one of the prominent "New Looks" now in the past two to three years. 

This "Cross Processed LOOK" that we are seeing so much of these days...and different color versions of it....came about in the film days when color print labs processed our negative films in slide film/E6 chemicals by mistake!  So, the whites went toward yellow... and the darks became purple or blue.  We thought that that LOOK was a gross processing mistake  If our whites became yellow...we wanted our money back!  But now today... it's "The LOOK"...because many of us became bored with perfect colors after a while.  Think of it...whatever was "IN" 40 or 50 years ago...thats the new NOW trend today! Things get "Recycled" in fashion...Retro images, Thick Glasses, Pin Up images, Pictures looking all washed out, yellow casts, blue shadows, red or orange light streaks on the edges of films, and of course less than perfect skin tones.

To get a bit practical for a just second....we can easily make our perfectly taken images of today to look like this older style or look rather easily... by using transparent curve adjustment layers in photoshop.  By pulling the blue curve down on top right...we create yellow whites... and by sliding the bottom of the blue curve up... we can get the darks to go blue.  Pull down the green curve in the middle... and now you have darkish tan-lined skin.  Many of the new trendy looks today are being created by experimentation by designers and photographers using curve adjustment layers... and playing with them until they get something thats obviously different... but pleasing, and maybe even trendy looking, or very artsy at least.

So, One way to understand a Look... and then re- manufacture that look for yourself... is to look at the white, gray, and dark parts of an image.  Look at the pure white areas of the image...what color is the white contaminated with today?  Make a curve adjustment layer and dial in that other color in your image...and there you go!!!  Copy cat trend-setter!   Look at the midtones...are they natural or neutral...or has someone darkened, or purpled or made the midtones some other hue?  Then look at the blacks...are they black or blue, or purple, or greenish.  Make up another curve adjustment layer and dial in your look! ( BTW...if you use the mask that comes with an adjustment layer...and invert it to black...then you can selectively paint in the new look color where ever you want it... however strong you want it... you could even have several contaminating colors...and selectively paint them in different parts of the picture to  "Create a Mood" or "Create a Look".)    Many of todays LOOKS are just color shifts... creatively applied... in a new way.

The Photographer of today now also becomes the artist...the new trend setter... all because he has deviated from the boring accurate color look.  He's a creative genius!

The designer or photographer has now also begun processing images with unique lighting techniques that add some special new look, drama, or additional emphasis to the image.  At least hes not doing it by tricky post processing in Photoshop God Forbid...at least lighting art manipulation is real.

This is just ONE way to look for...and how to Recreate... the new LOOKs.  Look for the color contamination areas... are they different colors...are the blacks crushed... are they off color... is the skin moody instead or perfect playboy pink/orange?  Thats easy...you can Re-Create it by using those clear, transparent, non-destructive adjustment curves...OR... YOU can create YOUR OWN... New Artistic, Trend-Setter, LOOK Yourself.  How artistic, or experimental, or out of the box are you? 

See what was happening 40-50 years ago...and bring it back for a new trendy magazine spread. LOL