There are Ignatian principles of discernment, and here are some examples I think you might find them helpful.
We already know a great deal about God's will. It is given to us in the Scripture and in the teachings of the church. IF what you will is not in harmony with both of those, then be assured: it is not God's will.
Then you add in spiritual counsel and direction. With a priest, or other faithful person, what do they think? Two heads are better than one, and again, if it does not pass there, it is not God's will.
Prayer--when you pray about doing what you want to do, do you feel or experience any answers?
Consolations and Desolations--when you think or act on the thing, do you feel peaceful and happy, or anxious and scared?
Emotions and Preferences--God created us uniquely with likes and dislikes, and a termperament. If your plan is in line with those, then it may be God's will. Someone who hates the sight of blood is probably not called by God to be a surgeon.
Circumstances--God is the God of all circumstances. If the circumstances do not line up with what you are thinking of doing, it might not be God's will (if you meet a girl half online way around the world and neither of you have any money to meet up, then it's probably not His will).
Reason--does it make sense? Using your head, which God gave you, can you see a way to do it? If not, then it's not His will.
And easy way to test your discernment is to decide, and then to act. He will let you know pretty fast if you did the wrong thing.