How do I make my lucid dreams more vivid?

Ive been lucid dreaming for a while and my lucid dreams tended to mostly be pretty vivid. But the last 3 weeks straight (except maybe 1) all my dreams have been so unvivid. I never had to do any methods or techniques to make my dreams more vivid they were just naturally vivid. Its like a switch just flipped in my lucid dreams. Ive still been writing down my dreams but they just arent vivid. Is there any techniques I should use or any tips u guys can give me