Record Them All
If you want to interpret your dreams, you need to make sure you are keeping track of exactly what insanity your sleeping mind dumps all over your brain. This means that you need to write down your dreams first thing in the morning, every morning. All of your dreams are packed full of meaning. Whether your subconscious has cooked up some unholy mishmash of every embarrassing moment you ever suffered or you spent another night dreaming about that old flame running back into your arms, you need to write it down.
All of your dreams means all of your dreams. Everyone is quick to record dreams that involved them fighting dragons or that were filled with clear mystical symbolism. Those boring dreams about being trapped at work, however, need to be recorded as well. There is meaning in even the most mundane of dreams, and they are often critical parts of patterns. If you skip dreams, you will be missing pieces of the puzzle.
On nights where you do not dream, simply write down that you do not remember any dreams. The simple act of keeping track can encourage your brain to better remember your dreams when you find yourself stuck in a dream drought.