Start by testing your DSLR to find out if you can use it to take infrared photos. Point a remote at your camera and take a one second photo. If your camera records the light produced by the remote, you can take the next step – buy an IR filter. The Hoya 58mm RM-72 is a good choice. Be sure to get the correct size for your lens. The link pictured in this post is to a 58mm filter. Expect your exposures to be extremely long because the filter blocks out almost all visible light. The example photo was shot at f/11 and 30 seconds.
You will need to compose the shot and prefocus your lens before putting the filter on the lens. I use back button focusing so I don’t have to switch focus mode. If your camera has live view, use it. Everything will appear red. To take a photograph like the example, you will also need to set your custom white balance. With the filter on your camera, fill the frame with something green – grass for instance. I used a green screen cloth. If the white balance is correct, the sky will be brown and land blue. To make the sky blue, use Photoshop to swap the red and blue channels in the photograph.
The infrared photograph below was taken at the Morikami Museum and Japanese Gardens. It is composed of ten images stitched together using Hugin. The exposure for each image was 45 seconds at f/8 and ISO 100. NIK Silver Efex Pro 2 was used to convert the image to B/W.