Suppose you write in first person. That means you say, "I walked down the path." Third person means you say, "She walked down the path." Let's forget about verb tense for now. If you want to write in present tense, then go for it. However, you're not as likely to have me as a reader.
Second person is possible, but incredibly awkward. Speaking to the reader is sort of like breaking into their apartment and acting like a serial killer. "You are walking down the path." The poor reader might think, "No, I'm not! Wait! Am I supposed to be walking someplace? But I'm sitting here reading. I don't want to walk elsewhere. It's hard to read when I'm walking!"
So, let's just say that second person is out of the picture. I really couldn't advise you on how to do this with any grace or style. If you insist upon second person, then I commend you, but don't expect to sell a lot of books.
Okay, 1st person and 3rd person are both fine, but what if you want to get into the head of another character, perhaps the villain? Can you do this when writing 1st person? If both your main character and your villain are talking aloud referring to themselves, it might be a tad confusing, but it's doable if you carefully divide scenes and chapters and make it entirely clear who the "I" is in each. Also, you'll need to be watchful of voice. Oh, right. Voice. Did you think everybody talks exactly the same way? Of course, your MC is nice, good, heroic, etc. and your antagonist is mean, awful, and villainous. Here's some first person examples if you decide to present both MC and villain in first person:
"I walked down the path, my heart yearning for any sign of my beloved, but I continue to be ever watchful of signs that Mr. Blackness had passed this way."
"I stood in the shadows, watching the poor, sad sucker meandering down the path without a clue that I've got his beloved stashed in a dungeon guarded by ogres."
These examples, of course, are exaggerated to make the point of voice incredibly important when you're writing with multiple points of view.
Easiest to do is third person. Everybody can have their say with little difficulty for the reader recognizing who's the star of a given scene.
Thing is, 3rd person is the writer's voice, the omnipotent story teller from on high (imagine your god-like presence hovering over the characters in your work).
Still, separation of points of view by scene or chapter is the best, easiest, cleanest way to keep the reader on track. You can change points of view between paragraphs, but expect your reader to have to backtrack to figure out who is out front in the story.
If you think you absolutely need to change POV without a scene or chapter break, then your last resort is a paragraph break and a time or place changing word to allow the reader a moment to switch gears.
Fred walked along the path, hoping to find some clue to Hilda's disappearance. MEANWHILE, Hilda pounded on the bars and screamed, desperately hoping to attract attention.
Here the time/place changing word is MEANWHILE. It signals the reader that the story is jumping elsewhere.
Stick to 1st or 3rd person. Change POVs only on a scene or chapter break. Keep the voice consistent to the character.
See? That's not so hard, is it?
Excerpt from "Missing, Assumed Dead"
These scene fragments illustrated changing POV using a definite break between the first part which is in the 3rd person point of view of Ray. It's a flashback to a time when the main character isn't present. Rather than just having Ray TELL Kam what had happened, the point of view shifts to Ray in the past. Both the scene break (* * * *) and Kam asking Ray a question, returns the POV to the main character.
George glanced at the copy of Riders of the Purple Sage on his desk. “Why don’t you go, Ray? You’re his friend.”
“Yep, but he’d think I was buttin’ into his bizness if he’s okay. If you go, you can say sumthin’ about looking for someone else or what not.”
“So, I should lie to him but really just be checkin’ on his welfare, eh?”
“Yep. That’s what I’m thinkin’.”
George swung his legs off his desk and thumped his boots on the floor. “Well, I s’pose that fits under the category of law enforcement.”
Ray suppressed a smirk. “That’s what I thought. Somebody official should do the checkin’, and that’d be you.”
“I’d be happy to do my duty, Ray. I’ll head out that way tomorrow morning. He prob’ly just got tired of your burnt burgers.” George leaned back in his chair and put his feet back up on the desk “When I get back with the good news he just didn’t want to come to town, I’ll sure as hell let you know.”
Ray nodded. He left George’s office and headed back to the café and his living quarters in the back.
* * * *
Kam leaned across the counter. “What did George tell you?”
“He didn’t tell me nothin’.” Ray shrugged. “I asked, but he just said the judge was takin’ care of it.”
Mitch’s heavy, black brows formed a V. “Ray, if you know something the sheriff should hear about, you need to say.”
The old man took Kam’s drained glass and refilled it from the pitcher. “I don’t know nothin’ for sure, so’s I’m not sayin’ no more.”
Prejudice, murder, insanity, suicide: Every small town has its secrets.
When Kameron McBride receives notice she’s the last living relative of a missing man she’s never even heard of, the last thing she wants to do is head to some half-baked Oregon town to settle his affairs. But since she’s the only one available, she grudgingly agrees.
Working on a hunch and trying to avoid the Judge’s henchmen, Kam probes deeper into the town’s secrets and finds almost no one she can trust. With Mitch’s help, she peels away the layers of prejudice, suicide, murder, and insanity. But someone in town doesn’t like her poking around, and when they show their intentions by shooting her through the police chief’s office window, the stakes are raised. Kam must find out what really happened to her dead relative before someone in this backward little town sends her to join him.
And she thought Oregon was going to be boring.