Sometimes your story needs to have number of viewpoints. This isn't the easiest kind of story to pull off. You are asking the reader to invest in a number or characters. One trick to make this work is to show the reader early on that this will be the form of the book. I've written many stories where there are a number of viewpoint characters. Besides letting the reader know there will be more than one character telling the story, making the break clear is important. In my stories following this pattern, I try not to switch viewpoints within a scene. I often make a complete break between the viewpoints or I start a new chapter or scene. This method also allows the reader to perhaps move to a different geographical area than the one currently used. So take care and only make the changes in the viewpoint when there is a need for a different view on what is happening in the scene.