how do you make a see through outfit appear more transparent in photoshop?

 Have you ever heard of Google?

 A little guide below, though I never really had great success. I think your imagination may have to come into play here.....

Step 1 - selecting your photo

- You will need a decent photo. Sheer is not the only characteristic the photo must posses, but it is an important one. Black sheer, in my experience, will not work, at least not nearly as good.
- The material itself doesn't matter as you can see from the examples below, as long as it's sheer and a light colored material, you should be fine.

Step 2 - selecting the area to "X-Ray"

- Try to only select the area in wich you are editing, don't do the entire image or it will look terrible. For this you will need to use the "Magnetic Lasso" tool and outline the specified area.
- Once the area has been selected, right click within the outlined area and choose "Layer Via Copy." This will make a new layer from the selected portion.

Step 3 - Obtaining "X-Ray" look

- Next, go to "Image" --> "Adjustments" --> "Levels." From there you can play with the slide bar to achieve the best effect.
- From here you can start to get artistic, play with other levels like, colour, contrast, brightness, and most importantly the "Dodge" and "Burn" tools to perfect it.

Other things to use...

1.) Adust the levels - Image->Adjustments->Levels
2.) Adjust the brightness/contrast - Image->Adjustments-> Brightness/Contrast
3.) Selective Colors - Image->Adjustments->Selective Color (I use whites, blacks and neutrals)
4.) Color Balance - Image->Adjustments->Color Balance (very sparingly or even not at all)
5.) Hue/Saturation - Image->Adjustments->Hue/Saturation (if needed, most of the time I do not use this)

[quote user="jdizzim"]

how do you make a see through outfit appear more transparent in photoshop?

[/quote]

You can't really...

You can only enhance or diminish that what is available on the original photo. If you want stuff which is not there in the first place, you will need to superimpose parts of a second photo Having said that, basically what you would try to do - using one photo is:
1) select the area that you want to make more see-through (lassoo function)
2) use a filter to seperate the "parts" from the rest (ie clothes)
3) enhance the "parts" and/or wash the background (clothes)
4) then clean the edges of the area.

As this will be very time-consuming and probably not with noticeable result, I would suggest a few things:
a) use the best possible resolution for the original. If possible RAW format, if not the highest jpeg.
b) you will need noise filters and sharpening, to get the noise of the photoshopped part similar to the rest. I would use a plug-in such as NeatImage, as this is quite a lot better than the internal photoshop noise filter.  
c) when you have finished, save the result with as least compression as possible. Then for publication save again as compressed small format. If you ever need to re-do that photo, you can start from the high compression 'shopped' version and save loads of time.

- mike =)).