The good news is that experience is the best remedy for this. The more you do the work the easier it gets. Treat every day as a new learning experience and apply what you learn to the next call, the next day, and so forth. Trust me, it will get easier. But as I have told you before, you can't push it, nor create it; it will come with time.
If I could, I would make an experience pill or poultice to give you. I'm sure it would sell by the bucketful. But since there is no such thing, it's important to soak up as much as you can. This includes learning from the experiences of others. Don't just watch but observe the senior officers and listen to their experiences.
In the meantime, I fully understand the many elements that you must weigh in making decisions. Here is a traditional three-prong test I was taught that helped me and can help you make tough decisions on the job.
Legal
First of all, ask yourself, Is what I am about to do legal? Does it meet the constitutional, state, and local laws tests? What about departmental procedure policies and practices? Notice I said laws and policies, all plural. In just about any task you perform there are several policies that are applied, not just one or two. The same goes for the law. Are you operating under local law/codes or applying state laws to this case?