Theres a saying 'if you want something doing ask a busy man '. Quite likely because a busy person is organised , motivated so manage their time more effectively. I also think looking a different way that if your not busy you seem to be discouraged which has a very negative effect on your self motivation, you get lethargic , cant be bothered , lack enthusiasm. Just think of a day when you havnt got much booked in , nothing in the morning perhaps, you find you waste time in the morning which in turn has that cant be bothered effect on the rest of the day.
Its a vicious circle you have to sort , its more of a mental thing. You have to keep enthusiastic , your heart must be in it. Keep the go get it mentality , go looking for work and when you get it do it to the very highest standard. Remember people buy 'you' as much as the service you offer, are you a people person ? If they dont 'like' you they wont get you back !
Mike