The good thing about writing dreams down is that you can go back and look for patterns - things that show up in your dream on a consistent basis. You can then use these items to base reality checks off of. Even if you remember all your dreams, you really won't see patterns emerge until you write them down and then go back and analyze them carefully.

Let me give you an example of what I mean by finding items to use as reality checks (called dream signs). In my dreams, I have discovered that I dream frequently of semi-trucks. So, whenever I see a semi-truck in real life , I immediately do a reality check (or series of them). This will train my mind to do reality checks when I see trucks and hopefully will carry over into my dreams. When my subsconscious sees a truck in my dreams it will remember to do a reality check and I will discover I am dreaming.