To have more vivid dreams the trick is to focus on one thing at a time during the dream or you can shout "Clarity" or "I'm dreaming" loudly once you know that you are dreaming. If you really pay attention to your daily life, you see that most of the time we're not aware of what we're doing unless we stop and start being aware. Try to remember what you did yesterday and you'll see it's very murky and doesn't have much detail unless you were aware. It's almost the same during a Lucid Dream, stop and focus on one thing and the world will have more details. Also vitamin B will help you to have more vivid dreams