Let me just say that I hate reading single POV stories. Not in this day and age. They seem one dimensional to me and, if your other characters have any kind of depth, I would like to get to know them. Getting into a character's mind is different from being told about the character. We keep hearing about showing instead of telling. Show me the character, let me feel them.
Now that I have said that, let's talk about writing multiple POV (point of view).
A POV is a character's perspective, how he shows you the story from his eyes. An effective POV will show you the way he sees things, what he is feeling, his intentions and how he proceeds/grows as the story progresses.
The more POV in a story means the story has a more complex story-line. The plot is highly developed with many characters intertwined and so needs to be told from different angles. Most crimes thrillers have this kind of story. You will see the protagonists POV, the antagonists POV, a supporting character and perhaps another minor character.
Making the switch in your story can be tricky. There are mainly three ways to switch your POV effectively and not confuse yourself, or the reader.
1. The chapter switch
You may switch character's viewpoint with a new chapter. This is very effective and the easiest way to go about doing this. The trick is, you must introduce the new character in the old chapter so as not to jar your readers with a completely new character which they knew nothing about. This switch is recommended for new writers.
To use the chapter switch you must inform your reader by either using chapter headings to tell who it is, or state the name within the first or second sentence. The reader should not read very far before knowing who they are reading about.
2. The Scene break – or paragraph skip
Another effective and very popular way to switch is by using a new scene to switch.You do this by breaking the scene with four asterisks between paragraphs. If you want to switch POV within the same scene put a quadruple space between paragraphs (assuming you are already using double space for your manuscript). Similar to the chapter switch you must not let the reader read too far before knowing whose POV it is.
3. The paragraph switch
This switch is used by many experienced writers. It is tricky and if you aren't sure may cause problems. The secret is that you must state whose POV it is at the beginning of the paragraph so as not to confound your readers. You cannot switch mid-paragraph.
A multiple POV story is great. However, you need to manage the number of POV based on story word count. A flash fiction of 500-3000 words only need 1 POV. A story with up to 10,000 words can have 2 POV. A novel over 40,000 can have 3 – 4 POV.
Having more than 4 POV is stretching it a it and might complicate your story more.