Although there is no right or wrong way to do ICM photography, there are some guidelines that may help you get started.
Camera Movement - I have found most success in moving the camera in parallel or perpendicular with the landscape I am shooting. When I have photographed in the woods moving the camera in the vertical plane of the trees has given me the most success. In the desert or along a shore I most often find horizontal movement gives me the best results. While shooting in the mountains twisting and turning during the exposure achieves unusual and unexpected images.
Exposure - My best exposures have been between 1/5th second and 1 second. You have a personal choice here. By using shorter exposures and/or less camera movement I can create an identifiable landscape. Some ICM photographers choose longer exposures with greater movement thereby making the image softer, more color field like. Their images are more abstract and often very colorful and beautiful.
Mix and Match - It is okay to layer images and play with blending modes and density. I do this on many of my images. I have found similar images overlaid often create a ghostly lines and intense colors.
Neutral Density Filters - Three stop ND filters and even polarizers can be used to reduce the light for longer shutter speeds. However, on a bright day in places like White Sands National Park you might need to use up to a 6 stop ND filter.
Rules? - All of these rules are made to be broken.