I've actually been trying to visualise more, especially more vividly and with more detail. Sometimes I have trouble visualising, but I don't seem to have trouble having dreams. My visualisations are often too vague to be very useful, although I am oddly more visual than verbal in my nature. I can have a difficult time focusing when I am going to bed at night, so if I am trying to focus on something while falling asleep, like lucidity or just dream material, it can be difficult for me to avoid wandering mind. I am considering taking up meditation.