DSLR's are great for IR. I use the Tiffen 87 but also have a Hoya R72 that i havent got a chance to play with yet. Your camera will do very well with both. Some other tips I can suggest from looking at your current gallery would be.
1.Shoot with your back to the sun, shooting into the sun with IR can be a problem.
2. Make sure your shooting raw and use Nikon capture to raise those overall exposure of the image. Nikon's D-Lighting is far better then photoshops. As you will see in my workflow I use it to get my image to the levels and whitebalance that i want before sending to PS in 16bit.
3. Take a look at the EXIF data on my gallery. All of those images so far are taken with the Tiffen 87, but I look forward to trying the Hoya.
Here is my IR workflow.
1. Set camera to manual mode, and raw data.
2. Find a nice bright patch of grass, and custom white balance on it with filter.
3. Set the camera up and compose, and focus with the filter off.
4. Turn focus to manual, (To stop it from hunting around with the filter)
5. Put the filter on and check exposure, adjust the shutter speed until you are over exposing the image by quite a bit. Take a few practice shots to get it so that it is nice and bright but not overexposed.
6. Take the photo, and repeat steps 3-5 till you have lots of pictures.
7. Transfer your images to your photomanager (i use picasa 2)
8. Pick an image that looks good, and open with Nikon capture or Adobe Raw
9. Tweak White Balance or fix it if you forgot to set a custom one.
10. Adjust lighting and exposure
11. Import to PS
12. From here I have a PS script that does the following
1.Creates a Channel Mixer layer with the following settings
Red Output: Red = 0%, Green = 0%, Blue = 100%
Green Output: Red = 0%, Green = 100%, Blue = 0%
Blue Output: Red = 100%, Green = 0%, Blue = 0%
2.Creates a Curves later above that, with Auto (I tweak it later)
3.Creates a Saturation layer above that with the folling settings
Reds: -40 saturation (Always have to tweak this)
Cyans: +30 saturation
Blues: +50 saturation
13. From here you should have a image that is usable as B&W and almost there for colour. But from here on every image is very diffrent. Here are somethings that I usally do:
1.Create a new layer and run Noise Ninja on it. Use a layer mask to apply it only to the sky and water areas.
2. Soft light layer (create a new layer and apply softlight blendmode)I use it to enhance tones a bit.
3. I usaully end up with a couple levels layers with masks to add contrast to specific areas, so I will adjust levels till the high and low lights clip, then mask those areas to bring the detail back.