How do you know when you hear God's voice leading you?
In the concept of leading me in the Word, I receive revelation, understanding and clarity. If it's an action, I try my best to confirm first if it's ok. If the reply doesn't seem right, I pray to silence all voices not of Him before inquiring again and listen. If He doesn't answer at all, most likely He wants me to be still or 'wait' meaning not do anything or not do something until an appointed time.
For example, I'll ask "Daddy, is it okay if I go grocery shopping today?" He replies "No, I want you to stay home." Then I'll pray: "I silence all voices not of Yahuah God with the Fire of the Ruach HaKodesh and the Blood of Yahushua in Yahushua's name." After asking again and hearing the same reply, I won't go.
God probably had me either avoid a car accident, sinning or potential backsliding in any area I'm weak or prevent overspent funds, or needed me to have the money available for something or someone in the future. He may need me to perform an 'assignment' for Him or learn a teaching I might miss if I'd left that day. The 'potentials' list goes on.
How do you determine what is your opinion/thoughts vs Gods? Would love to hear your experiences. God Bless.
My experience & relationship with God for thoughts/opinions, if they're not in alignment I do my best to cast all thoughts and imaginations down bringing them into captivity sending them to the feet of Yahushua to be destroyed or sent back to the enemy (if they're from the enemy) per 2 Corinthians 10:5.
I try not to have too many opinions and thoughts as they can either get me into trouble or I may miss a message He's telling me hence the above prayer. I fight against my flesh daily and the enemy especially during a fast. I still have a broken hedge of protection that's in the works of being fixed.
He'll answer questions I've had about His Word when I'm ready or if a prophecy hasn't come to pass yet. He did that today as I inquired why one woman's ordained husband hadn't arrived yet and I heard the words "He's been delayed." I replied "Ok, but why?" and I received no reply most likely because it was none of my business

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4 hours later, the woman I inquired about popped online to give a prophetic word from God via Periscope. She said God has been delaying blessings from many as they are not ready to receive them yet due to many reasons her included and He did not reveal it to her either.
The majority of God's reasons were people needed correction of behavioral characteristics or habits, they had hidden unforgiveness or past trauma, hidden unrepentant sins, their souls were damaged and unhealed from previous trauma and needing healing or cleansing, bad spending habits, not mentally prepared, etc.
In this situation, sometimes God will use another prophet to reveal the answers so He will receive the glory and teach others to be mouthpieces for Him in their daily walk and relationship. There's no limit with God of course on how He wants to answer us.

Hope this helps someone in Yahushua's name.
Shalom and be blessed,
Bro. Daniel