Two people, same experience, but responded completely different. One just observed it, and worked out a different strategy. The other judged it, and ended up in turmoil. Getting the idea? So if you've got judgements in your heart, it'll filter all discernment, so discernment - practice ridding your heart of judgements about people, and learn to be an observer. To be an observer, you ask the question: I wonder what this means, rather than: this means that. See? You ask the question, what does this mean? What am I feeling? What am I sensing? What does this mean? You let God help you see His perspective on it. Jesus said: I don't judge as the world judges. He said I judge righteously. I don't judge what I see, I judge by what my Father says to me, so He judged things on what He heard from God.
So how can I develop the area of discerning of spirits? Very, very simply. One, I need to deal with the issue of judging in my heart that will cloud my ability to sense; two, I can develop my sensitivity through fasting. Fasting and prayer helps me develop sensitivity to the Holy Spirit, and then what you need to do is, learn how to identify what you feel when you're in different situations, identify impressions you have when you're talking with someone, when you are meeting someone, when you come into a meeting, when you come into a room. When you go to different places, look for chances to identify what your first impression is. The first impression is usually the one that impacts you as you engage something, then you just move out of that, and start to reason everything out, and interact with it differently. But when you're a spiritual person which you are, you tend to be more sensitive, so you can feel things or sense things quite easily, and so try to, when you sense something, ask this question: what do I sense? What impression do I have? What am I feeling? Try to just get a name for it. Don't dismiss it. Just enquire, Holy Spirit, what is that? Then the next question; what do you want me to do with that? What does this mean?
If you judge, it must mean this, you've then lost your discernment. If you just say Lord, what does this mean, and how do you want me to deal with this, you'll start to then develop a lifestyle of being able to discern things, so there's heaps of places that you can pick it up. One of the places to pick it up, is when you meet people. When you meet people, just come with an open heart and shake their hand and look them right in the eyes, and just let them interact with you. As they interact with you, you'll have an impression come. Try to identify what the impression is. Listen for the things the Holy Spirit drops in your heart. You walk into someone's house, what impression do you get? What does the atmosphere feel like? You walk into a church meeting, what does it feel like? What does the atmosphere feel like? When everyone's worshipping, or things are happening, what does it feel like? What does it sense, is there? Develop, practice discerning, or exercising your senses, to listen and identify impressions you have about situations, and then act as an observer, not a judge; oh, that's interesting, I'm feeling this. I wonder how I should respond? I wonder what God wants me to do? So you don't move into judging mode, you stay in discerning/working with the Holy Spirit mode.
Now notice Paul went for several days before he turned around to the woman and rebuked the spirit. In other words, he waited until he had actual wisdom from God what he should do. You notice this, if he had stopped and reacted on the first day, he'd have been in jail straight away, and had no chance to do any ministry at all, so he didn't immediately address what he could see was the problem, until he felt the Holy Spirit show him: this is what you need to do, do it today. A lot of people can't handle that. They pick something up, they want to deal with it straight away. That isn't always how God works, because dealing with it straight away can create more problems than what - you may solve one, but you've actually created something bigger, and different. So if Paul for example, had turned and rebuked the spirit that same day, all those days that he was able to preach and minister would have been cut out and cancelled short like that, so he knew there was a spirit, but waited until the right time, and then turned and dealt with it, and that triggered off a reaction in the whole city towards him. Shortly after he exited the city.