This may be the real reason you got Photoshop...

You want your prints to print the way you see them on your monitor, a work of Art!

Just as a check before you start make sure you have been working with the right color space.  ProPhoto RGB.
And, verify that the image has been set to 16 bit (this actually makes a big difference!) You more than likely already made these presets in Camera Raw!
Menu: Image > Mode > √ (Check) RGB and √ (Check) 16 bits/Channel
 Before you begin load a duplicate of the image you want to soft proof. Use the Menu Bar item "arrange documents"

We will want to make our soft proof emulation (what the print will looks like on paper)  -- to the way it looks on your monitor!
in order to do so we'll have to make some "tweaks" to the softproof image.
Select the Menu Item:
View > Proof Setup > Custom...
and make the following settings

1. Set Color profile you made or provided for a specific paper and printer
(In this case the profile for my Canon Printer was supplied by Red River Paper, the manufacturer of the Polar Matte paper)
You may have made your own profile, or you are using the profile for the paper supplied by your Printer manufacturer.
For my Canon Printer, when I'm using Canon Paper, the profile is BJ Color Printer Profile 2000.

renderintent2. Rendering intent: (Methods for dealing with Out of Gamut Colors)
You have two choices (Saturation and Absolute Colorimetric are technical intents and can be ignored) the choice is yours based on aesthetics (how the result looks to you!

a. Relative Colorimetric Colors out of Gamma are "chopped off" (based on tones from light to dark) The results generally darkens the image.

b. Perceptual Intent: Compresses the colors according to the print profile (Based on color to color changes ) generally de-saturates and lightens the image.

3. Since the purpose here is to see what the print will look like when printed! Check Simulate Paper Color

4. Will show you by simulation what it'll look like when printed... UGLY? Well maybe... Sometimes the changes are quite subtle...



Fixing the images colors for print

Tweaking the Hues, and slightly increasing the colors dynamic range.

Generally you'll want to ensure that black are printed as blacks, and you'll want to tweak the colors Dynamic range with the Curves palette and bump the saturation of the colors with the Hue/Saturation palette.

1. Set Blacks

Use the Menu
Select > Color Range
Use the eye dropper to select the blacks and set fuzziness to around 25
Note
(Color range will open selecting the current foreground color! In this case it should be black, (00,00,00))
Click OK
To place the color selection on a layer use the keyboard shortcut
Control J (PC) / Command J (Mac)
this will copy the black selection onto a blank layer. (see the layers Palette)

In the layers palette change the black layer From "Normal" Blending Mode to "Multiply".
This will darken the black range by multiplying the value of the pixels...
(you can duplicate this layer to make the effect stronger or you can use the opacity setting to back off the darkening... )

Use the The Curves Palette to work with the dynamic range of the colors and Hue/Saturation palette to tweak the colors

The goal is to match the Soft proof to the Monitor Version...


The key word is " tweaks" so be gentle when you make your changes. Have fun! and Enjoy!!!

Oh, yes... save your soft proofed image as (for example) EnglishBay-Canoni9100-polarMatte-Relative.psd
In other words include the Name of the photo, what printer, profile and rendering intent you used as a .psd so you can do more tweaks if you so desire.
You can also save the tweaking layers by grouping them and apply them by "dragging and dropping" the grouped layers to a new picture.
Questions?