As in regular dreams, level of detail in lucid dreams can vary, from almost none, to more than when you're awake. Mine are typically just a little less vivid than in real life, but have been both much more and much less vivid. As for ways to increase realism, there are several techniques that work well.

The best technique is to be more aware of details in your waking life. Normally in our lives, we ignore most of the details around us, noticing little more than what we're focusing on. This leads to dreams with a similar lack of detail. If you make a strong effort to be as aware as possible of all the details around you, from all your senses, this will lead your dreams to become similarly detailed.

If you want to try increasing the detail from within the dream, there are ways to do that as well. One of the more successfull ones is spinning around in circles, while focusing on the feeling of spinning, and your sight. Rubbing your hands together, while paying attention to how that feels can also work. The one that works best for me is staring at your hands, and trying to see them in as much detail as they are in real life. In a couple of seconds, they should gain sharpness, and so will the details around you. All these methods also serve to increase the length of the lucid dream. They will generally work pretty well on their own, but you'll get the best results if you combine them with increasing awareness while awake.