unforchantly you cannot change the way your dream heads, the only real kind of dream you can possbily control is the dream that a lot of people have right before they go to sleep im not sure exactly what they call it but it's like a hazy type of dream in which you can control it, but once your actually asleep its hard to control your dreams.
i felt the same way I wanted 2 dream bout something..,it impossible on purpuse BUT I ATE B4 I FELL ASLEEP AND THOUGHT BOUT AN DREMT IT:) but I think bout this thing 24 7 so thts prob it worked