Hi Any, perhaps the best ways to know what the devil and his minions are up to is
1. be clear and certain about what the Bible teaches us about God, His word, His promises, His character, etc. (so be sure to remain ever vigilant in your studies .. e.g.
Joshua 1:8; Psalm 1:1-3; Psalm 119:9-11; Ephesians 6:10-17; 2 Timothy 2:15 ) and
2. make a point of always remembering everything God has done for you, and how VERY much He cares for, loves and wants the very best for you, so that you can always hear His loving "still small" voice over the din of our adversary's lies and deceit. IOW, train yourself to listen to God's voice, remember who He is and then continue to trust the One who loves you so, especially when the enemy's voice is the loudest and most upsetting to you.
I would also recommend a book that has been very important to my spiritual well-being, especially when I was pretty new to the faith. It's C S Lewis' little collection of short stories called,
The Screwtape Letters. It is obviously fictional, and yet, you will learn more about how to recognize what the enemy is doing and how he is attacking you from Lewis' book than you would ever learn from a theology on the subject (plus, while somewhat frightening, it is still a great read too

).
You can read it online for free
here, or you can buy the book or the e-book
here. If you can afford it, buy the book, because the particular edition I linked above includes many useful helps, histories, explanations, etc.
BTW,
The Screwtape Letters (which were initially read by Lewis as a series of live radio broadcasts) is written from the demons POV

So, for instance, whenever you see the word "Enemy" in this book, that's the demons' way of referring to God

(much of this is explained in the preface and intro, so be sure to read through those before beginning to read the book)
This is one of the reasons that it's so useful however, because Lewis exposes how they think so you can understand what is and what isn't an attack from them, and why.
Yours and His,
David