CRAP speaking of lesson I need to get on a stick! OK here we go:
So we've discussed what constitutes First, Second, And Third person narrative. The question remains: Can they be combined or used together in a narrative in a coherent and easily followed manner? The answer is: Yes, they can with varying degrees of difficulty.
Unlike research papers or other forms of technical writing the prose writer has much leeway in how and when he or she breaks with convention. The real test is whether the writing is easily understood by the reader.
Is the author allowing someone who is, essentially; blind, deaf, and sensory deprived to follow the story and create for themselves an image of the vibrant world being described? The problem with mixing narrative views begins when the reader becomes confused about who is talking or what they are talking about.
Let's begin tonight with narrative tense and then move into a discussion about voice. Narrative tense (or narrative time) detrmines the grammatical tense of the story; whether the action takes place in the past present or future. This is a common mistake for most writers and can lead a story astray fairly quickly, especially if your reader is picky about grammar!

Past tense- The events are fully formed, unchangeable and have already happened. All grammar must reflect this throughout the story. This has happened already and is now just a memory remember this! Incidentally this is the most common form of storytelling for English, Chinese and Portuguese speakers.

Present tense- The events are evolving and occurring right now. This is a difficult tense to maintain and in English this tense is known as "Historical Present." It tends to be seen more in
narratives that are conversations rather than full stories. Poetry can make use of present tense as well as song lyrics.

Future tense- All of the action takes place in the future. This form of narrative is extrememly hard to maintain and is rarely seen in literature. In this form the narrator is either completely omniscient or thinks he/she is. Frequently there is a sort of prophetci quality to the future tense story.

It is possible to write in the past tense and include what it happening in the present tense and even include some specualtion as to what the future will bring. The author just needs to set the scene and be sure that the tenses match!

Ok so far? any questions?

Tenses are a great big bugaboo for many writers who are so busy describing what they are seeing that they forget when it all happened! Or they are trying to sound more 'literary'. Break it down and keep it simple for the reader and you rarely go wrong.

Once you have decided on a tense you can choose what "voice" you want to use. Often this sort of seems to flow without must conscious direction but remembering to keep it simple will help you, as the writer, maintain a voice that is easy for the reader to follow.

The 'voice' is the perspective in a narrative, it is where the author combines and defines what viewpoint is being used and who, or what, is talking. This is where the combining of first and third perspectives is noticed most heavily and defined. Remember that outside of song lyrics and poetry, second narrative perspective is rarely found in prose. This is because, generally, the author uses the second voice to tell the reader how to feel, think and react. It can be rather aggressive and is meant to yank an emotion out of the reader they may or may not want to feel. When the author is describing a scene or telling a more indepth tale the second voice generally evolves into a reminiscence or a character's desires making it wander closer to first or third person perspective. This is fine and expected so it's easy to overlook.

Narrative voice- In narrative voice the author can present the story he or she is weaving, for example, by allowing the reader to view a character's thought processes, and those things that normally we cannot know about someone can be presented by the narrator. The narrator could also read a letter that was written by one of the characters in the story or simply recount a character's experiences. There is a degree of omniscience the narrator presents in that he/she/it knows things that, ordinarily, we don't know about the motivations, thoughts and feelings of others. Time isn't taken to get to know these characters we are just given the necessary information we need to form opinions or understand the motivations of the character.

Stream-of-consciousnes s voice- Utilizes, almost always, the first person perspective and attempts to replicate the thought processes of characters rather than simply telling the audience all about the actions and spoken words of the character. Examples of stream of consciousness voice are, but are not limited to; inner monologues, inner desires or motivations, and fragmented or otherwise incomplete thoughts expressed to the audience but not (necessarily) to other characters. This can be added into a larger piece of writing, such as a novel, to give more indepth study into the motivations and desires of characters so that the reader comes to know, from the character, what is going on inside of him or her.
This voice can be used in a shorter work with the narrative voice to prove that the narrator is speaking the truth but the author would come perilously close to crossing into an unreliable narrator voice if this method is used.

Character voice- Generally in most first and third person perspective writing an actual person is presented as the narrator. This narrator is no longer a "God like voice" but is another human simply telling a story. Keep in mind this human narrator may or may not be intimately involved in the actions of the story and may or may not be biased for or against the other main characters.
If the character voice narrator is actively involved in the plot then they are referred to as the viewpoint character. The viewpoint character may only have a periphery role in the story but they are intregal to the plot.
As the most common writing tool this is the most easily understood by most writers and readers.

Unreliable voice- This voice falls under the category of character voice but the narrator is someone the reader is supposed to develop a mistrust or even outright dislike of. The point is to use this voice to give the reader a sense of disbelief in the story or a level of suspicion about what is true or false, right or wrong. It can be used if the narrator is, perhaps psychologically disturbed, naieve, completely ignorant, has an unavoidable bias, is purposefully trying to decieve the audience, or is a child or child-like.
Generally this is handled in a first person sort of narration but if a third person perspective is maintained but the narrator is unreliable she/he may be thought of as using "Third Person Subjective." Although the thoughts and ideas are being presented as a third person narrative they are subject to the prejudices and biases of the character rather than fact as presented by the author.
Child narrators, because of their lack of worldly experience are considered to be unreliable narrators.

Epistolary narrative- Though charged with meaning this narrative is actually fairly common in romance novels, time travel stories, horror stories or other types of writings where a narrator is rarely utilized and the plot is carried by a series of letter or documents, such as a diary. If the author has collected many such "letters" then the work could be considerd to have multiple narrators who could be classified seperately, or the work could proceed without a narrator voice at all. The whole story could be one long letter; a series of diary entries; or a plethora of letters, diary entries, newspaper clippings or other forms of literary works "found" by the author.
This voice can be intersperced with action sequences where we are given a clearer view of what is going on between the letters or diary entries. Alternatively letters or diary entries can also be used to sum up the previous narrative or explain some point the author believes is important to stress.

There are, of course, further breakdowns of each of the voices but for our purposes we'll stop here. Remember when you are writing to choose a voice that suits your story. If your story requires you to change voice be sure to give your reader plenty of opportunity to realize that the voice is or has changed. A few lines of dialogue is rarely enough to effect this change well so be prepared to set some other groundwork before you change things up for your reader. One effective way to change perspective in a novel type setting is to use a chapter break. For shorter works the author would perhaps include a descriptive paragraph to introduce the change and then proceed with the new voice. Think of this as if two or more people are recounting a story bound only by theme. If the listener is to remain caught up in the tale he/she must be introduced to the new speaker!

Ok so if we make a study of the different voices commonly used in writing we can begin to mix it up with the proper respect paid to the reader. It is possible to combine first and third perspective in a story but it must be handled with care so that the reader doesn't end up lost, confused and/or worse, bored!

Second person perspective in a narrative generally becomes filler wherein the author begins to force the reader to relate to the story on a visceral level. It's easy to flip this to a epistolary type voice with a "letter", "phone call" or some other evidence collected by the narrator.

Any questions/comments?