Suspension of Disbelief

In all the morass of character and story and rhythm and arc and structure, it's easy to lose sight of the fact that the primary job of the dramatist is to have the audience lose themselves in what they are watching.

All of the above list, and more, go towards that. But here's what I think is the best 'assist' to that suspension of disbelief. Recognisable moments.

I don't know if that phrase has already been coined, or is even proper English, but by it, I mean those actions or dialogue which the audience can relate to and ground them in the story.

You have a wedding scene in an action movie? Have a shot of a six year old page boy picking his nose. No matter what happens next, the audience is with you. They believe this 'could' be a wedding.

Pulp Fiction is perhaps a good example, assuming you can write dialogue like early Tarrentino. The famous 'Royale with cheese' exchange both grounds the audience and serves as a great juxtaposition when they grab shooters out of the trunk. The audience is already with them, even to the extent that they can happily accept Uma Thurman drawing an imaginary square on screen.
Less is more is a very good and useful adage. But less can sometimes be less when it comes to immersing your audience. A shot here and a line there can make all the difference, especially if tied in to character. The audience MUST accept what they are seeing. Not believe, but accept.

I have a crap memory, but there are countless examples where a line or a shot is there just to ground the audience. And never forget the importance of 'background'. I tend to watch things like an audience and so don't specifically pay attention to what William Goldman called the 'shit-work' I.e the work that no one notices but without it the whole thing would fall apart. Take a staple 'great' movie like Casablanca. Shit work had already been done with the singer who went with the German to spite Rick and the guitar playing female, so that when Lazlo had them all singing the French national anthem, when we cut to them it really means something. Brought tears to the eyes, even.

'Moments' elevate a script. Tie them to theme, character and story and you've struck gold.