Are your scenes believable?

For most of us who write fiction it's plain fun; you can create a world, a story, characters and scenes, anything you would like to do or anyone you would like to be or meet. It's fantastic, isn't it?

So far, so good. But since we're not writing from memory, meaning something that happened to us, we rely on imagination. A lot. Especially in genres like Fantasy or Science Fiction we have to make sure that it's believable, realistic and logical. In a world that doesn't exist, the reader wants to be convinced that everything that's happening could be reality. Let's take my novel No Wings Attached as an example. My character Celia hears a voice, she turns around and looks at different people, anyone could have said something, as it always happens in public places, either in the supermarket, in the park or in the pub. If she would have been at home and hear voices, it would take the suspense away, make it unrealistic. Well, maybe not entirely, but then she'd be a case for the straight jacket.

Recently, I edited a friend's manuscript; he had a character in need to get out of a dangerous situation and the possibility to do so via a device, but my friend let his character hesitate for ten seconds, which would have been enough to be killed, so I recommended him to let him hesitate for only two seconds, which would be enough to shout a command and escape. Try counting slowly till ten, it's a long time.
Little things like that let readers stumble.

If you have a character that can jump (beam) from place to place and it's not wise to let him or her appear in a public place and walk around as if nothing happened. I bet you would be rather surprised, if not shocked if someone appears out of thin air in front of you. So check on how you would react and transfer it into your scene. Screaming, kids pointing at the person, fainting, running away in panic, people taking pictures, etc.
Think Superman, who always appears in an empty street. 

Same goes for books like romance or crime, thriller.
In case you  have a murder, what would happen in reality? How would the procedure be?
When an airplane drops out of the sky after one engine exploded and it's torn into half, what would the scenario be like? Would the air-hostess really make an announcement that they're about to die and everyone needs to remain calm? Try to imagine how naked  panic creeps up the passengers and crew, try to hear them screaming, crying, reaching for their safety kits.

The husband has a stroke in the shower, the wife comes in and finds him on the floor bleeding heavily because he's hit his head hard. Instead of calling an ambulance, she's trying to wake him up, cries and strokes his face.
Would you behave like that? Of course not, you would do it the other way round: first call the ambulance, then attend to the person.

If you try to feel and think like your character, then you should be able to make your scenes real, meaning fiction turns into reality for the reader, and that's what he or she asks for.