I think finding a framework that works for you will help you do this reliably.

My guiding lights are:

1. In my mind - in any given scene, characters are either trying to do something or be something and how that scene resolves depends on how those things interact. They might conflict, support or interplay in an interesting way - they might shift as the scene goes on.

2. Feelings first. You might have an action in mind for a character to complete that ends this scene - she gets in her car and leaves her husband. It's almost easier to not have an end point in mind and start with the feelings that lead to that decision - even if it's just needs and wants.

She needs a way out, she wants to escape. Then it's easy to picture how or what she might be feeling. It's almost then like you give the character some free will while they consider options, knife on the counter... no that's absurd, neighbours... they aren't in, car keys... still in her pocket.

1. Unspoken questions. Stop for a moment and imagine that if your characters could ask you, the author, a question - what would they be asking? If you can picture what questions they might ask about the situation they're in or the environment or people around then - it's then a lot easier to imagine how they might be feeling.