The Conscious Mind
The Conscious Mind is where you do all your day to day thinking. This is where you make decisions and where you primarily operate from in normal life. When you hold a conversation or watch a t.v. program you are using your conscious mind. Both the conscious mind and the subconscious mind think in pictures. If you think about your family members a picture of them will flash on the movie screen of your conscious mind.
You also can only hold one image on the screen of your mind at a time. For example you cannot think of a red apple and an orange in detail at the same time. While you might be able to project them side by side you are not able to see the grain in the skin of the apple or the dimples in the peel of the orange at the same time.
This ultimately means that you cannot think of a negative idea and a positive idea at the same time. While your mind might be able to flip back and forth between negative and positive ideas or images very rapidly, it is not able to hold those two images at the same time.
The Subconscious Mind
The subconscious mind operates in the background of your life and while you sleep. Dreams are a product of your subconscious mind. You can think of the subconscious mind as a computer program running without your help at all times. An example of this would be when you have suddenly realized that you have not been paying attention while driving and you are almost home from work.
The entire drive to and from work is a program that you have put into your subconscious mind through repetition. Your driving is almost automatic and takes very little thinking on your part. In fact without consciously thinking about going to the store when driving that pathway you will drive straight home. Your programming will take over and you will "forget" to go to the store unless you hold the image of the store at the forefront of your mind when driving home.