You should still write down a few words to trigger your memory of the dream. I quite often have 4 dreams to write down. When I'm about to write them down a minute later, I can only remember 3. So put down a few keywords and then you can start thinking about it in great detail.

When you become lucid in a dream, it can be extremely vivid and realistic. Doing things are amazing at the moment, the only thing which is kinda of a let down, is that the memory of it all fades almost just as quickly as a regular dream. So whenever you have a LD; Write it down!