There are many different ways that experienced workers come to know that someone is working on them or throwing for them. Instead of repeating what I've heard others say, I will only write on what I know from personal experience.
The number one way that I know that I'm being worked on is when a spirit tells me. I feel foolish for writing this, but I've talked to spirits ever since I was a little kid. Most of the spirits I interacted with where good. I did have the occasional experience with a dark spirit that other spirits protected me from. Also on a few occasions a spirit scared me greatly and then later I learned that the spirit wasn't dark but was just desperate to communicate with me. I quickly learned to set rules for the spirits on how they communicate with me. However, that's not the point of this blog entry.
Spirits are my first line of defense when it comes to knowing that someone is throwing for me, working on me, putting a curse, hex, or witchcraft on me, or just sending out negative energy. What will happen is that as I'm falling asleep at night, or as I'm waking up in the morning, a spirit will literally tell me stuff. Now, when a spirit communicates via an audible voice in this manner it's not like a living human. They don't talk like in a complete conversation. It's normally just a short phrase, such as, "You're under attack", or "There's a threat". Sometimes I recognize the voice as a departed loved one. Other times it appears to be a good spirit whom I don't know who wishes me well. Perhaps they are ancestors I don't know of. However, sometimes the voices are easily recignizable as people of other races, and some of them even speak in accents. So when this occurs, when a spirit gives me a warning, I know to start doing uncrossing, reversing, and/or protection work.
The second way that I know that I am under attack is by my dreams. I have the same dream over and over again every time I am under attack. The dream always involves me being in a house that I know is my house, even if it doesn't look like my house. Outside there will be a threat of some sort. It could be a robber, a killer, an animal, or even a monster that is trying to break into my house to get me. Every time I have this dream I know that it is a warning that someone is attacking me and I need to do uncrossing, reversing, and/or protection work. Well, there was one time where I had this sort of dream and assumed I was under attack but the dream came true; hence it wasn't a warning. In that dream I saw the shadow of a giant spider in the window. Later on a giant spider crawled on my arm. So that was the one instance where this sort of dream wasn't an actual warning of a spiritual attack.
Now, if by chance I don't listen to the spirits or heed the warnings in my dreams then the third way I know that I'm being worked on is via physical complaints. My scalp will start to itch. My muscles will get tense. My mind will be scattered, I will be stressed-out, and I will get angry over trivial things. If I dont' catch it a headache or even a migraine will soon follow. I will also feel like something heavy is on my back, like I'm suddenly carrying extra weight on my shoulders for some reason. Theses are all warning that I'm under attack. In the past I did make the mistake of not heeding the warnings from spirits and from my dreams and I let it get to the point where the attack was manifesting as physical complaints. I am now a wiser and stronger worker to be able to nip it in the bud and send everything back to the poor sap(s) who decided they were going attack me.
As new workers come into their own power they will also begin to notice and understand how spiritual attacks manifest for them, how they are warned of them, and what signs to look out for.