Allow me to share an interesting experience. Years ago when I first began the adventure of manifestation, I used the carrier wave approach that InnerCalm is describing. I started by getting into a lotus position with good posture. Then I accessed a theta brain wave state. Once I felt the familiar place of theta, I was ready to start my intention.
Problem. I lost my focus and began to "day dream" once I entered theta.
I learned a valuable lesson about day dreaming in this theta state.
In the vision (day dream) I got into a kung fu fight with a very big Afro-American street fighter. In the vision we were going toe to toe until he got in a very powerful shot to my rib cage. This snapped me instantly back to an awakened state. I was in searing pain and when i went to move it hurt even worse. There was also noises coming from my rib cage upon movement. The pain never subsided and hurt with every breath.
I went to my doctor who diagnosed 3 cracked ribs.
It is important to keep your focus and not lose yourself to random thoughts in a state where manifestation is instant.