Well, it's the same for every camera, you know? Film needs enough lighting to get a good image. Use your manual controls if possible and try to avoid the auto stuff like exposure. Take the time to set up and frame your shots, since the film goes through quick and is expensive.

I'm assuming that the camera is in good working order. It's especially important with 8mm because the image is so small that any problem with the camera (unsteadiness, flange depth, etc) are magnified.

After that, the most important element is the element gathering the light. If you've got cheap lenses, you'll notice because again, every mistake in 8mm is more noticeable because the negative is so small. If you've got a choice on glass, get the best glass you can.

You'll also notice problems with exposure and focus more on 8mm, so be sure to be very careful with these. All errors will be magnified. 8mm is a good place to learn photography, because there's nowhere to hide, but conversely, it will only look so good. When you want it to look great, it's time to move up to 16mm or even 35mm.