Since dreams are a product of ones subconscious mind, the more clear or free the subconscious mind is, the more clear or lucid the dreams will be. To keep ones subconscious mind clear one need to free the mind of the constant daydreaming and troubling thoughts that can occur during the day, and this can be done either by fully concentrating on what one is doing each moment of the day or by controlling the mind in other ways such as concentrating on ones third eye or heart region or other chakra area during the day. Not only does this keep the mind free, but it also brings a great peace to oneself as the body is brought into a relaxed state from the controlled state of the mind. Much success in your efforts.