Even if you're observing yourself in the dream, you are still there. You are some being in the space of that realm. Thus, in order to do a reality check then one needs to practice taking attention away from usual observative functions (such as watching TV, reading, etc.) and doing reality checks in the midst of them.
In fact, from my own observations and analysis, I've deduced that I'm always doing something in my dreams...as in, taking part in some activity that takes my attention fully.
Thus, I've deduced that in order to resolve the dream state I'll need to make a habit out of reality checking as often as possible during concentration on any given activity.