The primary goal of scenes is to progress the characters and the story, and keep the audience from boredom.
1. Try to stay away from Sitting Down Scenes
Have as few sitting down scenes as possible in your step outlines.
Bar scenes, coffee scenes, eating scenes, sitting down scenes are generally boring.
2. Aim for many Surprises
In poor films, the story twists and turns are so predictable, which results in few to no surprises.
If possible, constantly push for surprises and more surprises.
Set up the audience to expect one thing, then deliver another.
A TECHNIQUE
Sometimes, when you're stuck in a story corner, the way out is to think: "what would the character do?"
At this point, think of the obvious. What's the most obvious thing that he or she would do?
Then, take the obvious and turn it 180 degrees.
(EG.)
There's a moment where the girl and boy are on the romantic precipice of a kiss. A kiss seemed too boring.
So, instead, the girl pulls her fist back and slaps his poised mouth.
The boy is surprised. But more importantly, so is your audience.
3. You need Foreshadowing / Suggesting
You need to setup the drama, like how jokes need to be set up in comedy monologues.
(EXAMPLE)
If someone's dog dies in the story, you want to foreshadow the dog, and its vulnerability to eating something that might be dangerous or his love for chasing cars.
Then, the audience anticipates. When it finally dies by eating something bad, or get hit by a car, it will have much more impact on the audience, since you've already set up the dog and it's habits.
(or)
Put a gun in a drawer and you'll have the audience leaning forward every time a character goes near the drawer.
(or)
You can even do it for the protagonist like how audiences could hardly wait for Batman to come on screen.
This creates anticipation, suspense, tension in the audience, which is great.
4. It's good to Tell and Retell your Message or Theme to the Audience
Act 1 to Act 3: Tell them what you're going to tell them, tell them again, then tell that what you've already told them.
It's like reiterating your point, or in general what you want to tell to your audience, throughout the film.