When you’re using Third Person Objective Point of View, it’s a case of giving just the facts. The reader is never allowed into any of the characters’ minds, nor given any of their feelings or emotions. The reader has to judge what the character is thinking or feeling by what they say, what they do, and their facial expressions - much like real life, in fact.
So, to clarify:
In Objective Point of View the reader has access to nobody's thoughts.
In Third Person Limited Point of View the reader has access to one person's thoughts at a time.
In Third Person Omniscient Point of View the reader has access to everybody's thoughts at the same time.
The advantage of Objective Point of View is that it’s a good discipline for you as the writer. It absolutely forces you to show-not-tell.
If you’re attracted to this style of writing, then make sure to observe people. (Well, all writers should be doing this, as a matter of course, but it's essential in this case.)
Watch how people act and react, analyse their facial expressions and their body language. Make a note of how they move when they walk, of how they sit, of how they gesture. Observe how people’s style of dress, their cars and their houses reflect who they are.
As already said, you still need to get it across to the reader what the characters are thinking and feeling. But you have to show it rather than telling it. Here’s an example, albeit one that's a bit over-done:
John laughed hollowly. “You’re joking,” he said. The neon light flickered on his face, turning it a ghastly yellow.
Veronica shook her head slowly. Her fingers were busy shredding her tear-stained paper tissue. “I’m not joking. It’s all true.”
John stood up and banged his fist against the wall, hard, once. He was shaking his head in disbelief. “I’ll have to leave now,” he said, his voice terse.
As I say, it’s hard writing, but done well, it’s a very powerful form of writing.
The disadvantage of using Objective POV is that it can lack intimacy.
For more on this, read the page on the Character's Point of View.
Also, I wouldn't recommend using this POV in First Person Point of View. You'd just have the protagonist relating what happened and what he/she did, with no commentary at all. The big advantage of first person POV is the level of intimacy between reader and character, and if you’re not availing of that, there’s no advantage to you in using that POV.
Now, having said all this, it would be very challenging to write a whole novel using this POV. Its just-the-facts pure reportage style does risk losing the reader's empathy with the characters, particularly with the protagonist. It would depend on the genre too - it'd be easier to for this in a thriller, say, rather than a romance.