Your IR image, if taken with a traditional 72nm filter, will look something like this. Here we have opened a RAW file in Adobe Camera Raw.
The first step that I do in RAW, is to neutralize the white balance, it really helps the exposure. Note the histogram above, and then here, after I use the grey-dropper (white balance tool in ACR) and click on a neutral grey area.
You can now, if you wish, desaturate in RAW. Or, you can leave it, and go B&W in Photoshop.
If you haven't gone to B&W, you'll want to do Channel Mixer, and modify the red & green channels. Check the monochrome box.
Give Photoshop's Auto Levels a try, you will be pleased with the results!
Let's add some Luminosity Toning. Cmd-Shift-~ (PC: Ctrl-Shift-~) to select the luminosity. Then New Color Fill Layer, choose your color (I like chocolate brown sometimes...)
Change the layer blend mode to "Color" and lower the opacity to taste. I like 15-20%.
Some sharpening, and you're done!