We can only practice using our dream memory once a day. When we wake up we try to remember as much as we can and if don't remember any of our dreams then we have to wait until next morning before we have another opportunity to practice using our dream memory. However, I think we can train our dream memory by training our waking memory.

How are you going to remember everything that goes on your dreams if you can't remember everything you've done during the day? If you can't remember the conversations you have during the day, you won't be able to remember the ones you have during your dream.

So, you should try to practice remembering what goes on during your regular waking life and it should help your dream recall.

ALSO, you can't remember something if you don't notice it when it happens. If you see someone but you don't notice (are aware) of what they are wearing at the time. You won't be able to remember what they were wearing later. So if you want to improve your waking memory you need to pay attention to small details from all 5 of your senses. This is the essence of meditation. If what I'm saying is unclear to you, then read more on meditation. A good place to start is. http://www.dreamviews.com/f12/dream-yoga-34263/

Also, pay attention to why you are doing something. Have you ever walked into a room and forgot why you went in there? Have you ever sat down at your computer or gotten on facebook to do something specific and then you get side tracked? Don't do that. Always have your intention in mind. This is important for having lucid dreams because often times we do things in our dreams that don't make sense. If we are aware of why we do things during the day we will be more likely to realize that we our actions in dreams are silly and have a DILD.

Also, have you ever been riding in the car and you lose yourself in a stream of thought and the next thing you know you have arrived at your destination? I think a similar thing happens in dreams. We zone out and then reappear in a new location but when we are trying to remember how we got from one place to another, we can't. Just like when we are trying to remember what was in between point A and point B in our car ride we can't because we zoned out. If you have more awareness during your car rides, you'll have more awareness during your dreams.

This has been a bit of a rant. I hope it helps.