If you ask a dozen readers, you'll receive a dozen preferences. That pretty much rules out any hopes of "perfect scenes." Hopefully you find that liberating. I sure do.
This is one area where outside eyes can be very helpful. The questions you should be asking (are we gaining anything from this scene? Does this scene move the story along?) may be harder for you to answer.
2. Want to make sure my characters are meaningful and when something happens they have that inner-perception/realization ...
I don't have anything to add on top of what has already been said.
I just fall back on my usual, which is to ask 'what is this doing for the story.' If it's making the pacing work, or offering insight into how the world is or how the narrator thinks, then woo. If not, boo.
That's where I would have trouble since, as an amateur writer, a lot of what I have helps to drive the story forward. There might be only one, possibly two sentences that make me question if it works or not.
Time wise, I try to gauge it as best as possible. There are times when I write one day and can immediately go back to writing the next, while re-editing what i've written. However, there are times when I need a very extended brake to get my juices flowing.
The primary story i've been working on for a year, I took a good three to four month break which i'm kicking myself over for right now. Don't know why, but each time I look at the story, nothing clicked. Felt like my ideas were running dry with each new word I typed out. It grew to the point the new stories I were writing for each chapter didn't have that "spark" I liked with the previous stories.
Right now, the story is still unfinished and in desperate need of an ending. With my renewed sense of devotion, I hope to remedy that problem. I really and truly do want to make this story as close to perfect/the best it can possibly be. I am using it as a template to help me understand what works, what doesn't, what might work, etc..., as well as the major issue of what people like in a story.
Have a story that was started close to four years ago that's brewing in my mind. That's the story I want to eventually publish.
*raspil makes an excellent point. I notice every so often people post stuff worrying over some element being perfect, to the point that they're setting an impossibly high standard for themselves. It's not that you shouldn't have standards in your work, it's that after a point you need to calm down a bit and just let go. Focus on the stuff that matters, know what you're trying to achieve, and just do the best you can. I kinda doubt you've ever read a book that was completely perfect. I haven't.
As far as suspense: all it is setting up information that will be revealed and delaying the reveal. The trick is to build up to the reveal and make it something the reader wants to know. Another way to think about this is conflict/tension. When you read a book, pay attention. Notice at the end of each chapter or scene, the writer has given just enough information that you understand some things but are left with questions about something else. You can't leave the reader with those questions if you've already revealed everything they need to know. If you're working really hard to tell the reader what it means to the character, you're leaving them with nothing more to discover. Let them ask first how the character ticks, then gradually show them how they tick over the course of the story.
And as far as generally trimming fat, I can only echo what's already been said. Focus on specific details, that is something that relates to the plot, characterization, or setting and really carries some weight. If the character is wearing a coat because it's freezing cold and that detail is important, fine. But do you need to describe it in excruciating detail? In most cases: no. The other thing to focus on is the prose itself. Make sure every adjective is doing valuable work, and nix the ones that aren't. Trim your phrasing, make it more elegant and succinct. Avoid qualifiers, use adverbs rarely and with extreme caution when you do. As far as characterization specifically, judge whether the inner monologue in these scene is really adding anything, consider whether a particular bit of dialogue is doing its work. Be willing to cut whatever is not serving the story in some way. You can only know what serves a story by knowing exactly what it's about and who it's about. You need to think about it in more mechanical terms.
the P word -- stop with that, for one, first thing. it'll never be perfect. what is perfect? you can whittle down the fat but lose the flavor of the story. just make it right. how? that takes practice and time. you can't make anything perfect because you're a human being. what you think is perfect an editor might think needs a total breakdown and re-write. what you think is perfect someone else might think is too vague and now your story is too dry. so stop trying to think perfect is a thing you can do and just tell the story the best way you can.
there is one mantra that i use: if it doesn't move the plot along, it doesn't belong (that's paraphrased from Vonnegut: "Every sentence must do one of two things—reveal character or advance the action." I like mine because it rhymes and is easier to remember).
just keep doing what you do until it's right, not until it's perfect. there is a difference and that takes, like i said, practice and time to know what it is. there's no short-cut.
And then we have curve-blowing mofos like George R. R. Martin who lovingly describe every color and rivet in his characters' battle dress, only to become a bestselling author raking it in on television royalties.
So yeah, you have to figure out your own balance. What makes your stuff pop might not work with someone else's corn.
I really have no better answer for this. It's something I've learned to gauge. When did I gain this power of figuring out when I've gone too far? I haven't a clue. It's just something I've developed. It's something I can just tell now. It more apparent when I try to force something in and not let it flow into the story.
Enough is enough when description and suspense-building or whatever gets in the way of the pacing of the story. My rule of thumb is that once you start skimming or skipping ahead as you read, trying to get to the parts where shit actually happens, then you know you've got too much fat in the story.
Personally, I don't think there's ever a time when you should climb up on a soap box and 'build drama' over a character's feelings or inner conflict. Your drama is in the description of the events taking place. If you set the scene and build the actions vividly, and actually place your your reader in the situation, then the reader will supply his own emotions. Trying to force emotions upon a reader almost invariably makes a narration sound preachy or histrionic.