Do I have your attention?
Action is something that's becoming more and more important in all genres. You could argue that action is less important in some genres, but I don't think that's true. I think it might just look different. There should always be some kind of tension and action. Whether that action comes in the form of some kind of fistfight really depends where your story is going.
One of the most important things to think about with action is whether or not your reader can follow. You can ask a close friend to help you with this. Sometimes action sequences are so fast that the reader can't keep up and doesn't know who's doing what. If your action sequences are complicated, you need to make them as clear as possible so the reader knows what's going on. Otherwise, they might skim past it and all your hard work will go to waste.
Another thing you have to remember is emotion. There are so many cold, hard, action-packed scenes out there, but with emotion, they become a hundred times stronger. You need to include this in the build-up as well as in the action itself. The reader wants to know what your protagonist is feeling. Are they petrified, over-confident, taken by surprise? We need to live it with them. Too much description will feel dry but don't get too distracted by your characters' emotions or it could slow everything down. It really is about finding the perfect balance and the flow of the scene.
The hardest thing I find with action is scaring myself before I've even got there. How can you improve unless you dive right in? I suggest just going for it. If it's terrible, you can rebuild in editing; that's what it's there for. But you need to write it. And trust me, you can do it. I believe in you. Stephen King said 'the scariest moment is always just before you start', and that is true more than ever with action. But you should write what scares you. It's the greatest way to improve.