Hello Darelor.
I am going to assume that you are using the same sealife strobe I got with my DC800 Pro kit.
The best advice I can give you is to first check your camera and strobe settings. I set both to automatic, since they are designed to work perfectly like that. You can look in your owner's manual to find out how, but the strobe is almost idiot-proof.
Having done that, remember that you are looking to reflect the strobe's light off of your subject and into the lens of your camera. Since your strobe is very offset from your lens, you must manually aim it to get the proper angle. It shouldn't be too much, since the strobe has a fairly wide blast. Just point it a little bit towards your target.
Beware, however, oversaturating your shot with too much light.
Also, have you tried using the clip-on wide angle lens, if you have one? I find it gives me a lot more leeway so I stand a lesser chance of screwing up a shot, since you've got more light coming into the shutter and thus the CCD. I really just stopped taking it off, except for cleaning after a dive.
Hope this helps.
Peace,
Greg