Don't flatter yourself
"For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places." (Ephesians 6:12)
When's the last time you sensed you were being manipulated? Or lied to? Or shined on in whatever capacity? I'd wager to say that it happens more than we think and in subtler ways than we'd ever believe. Paul, writing to the Ephesians, speaks of the overarching war between God and His people (angels, included) and the devil and his. But because we can't see with our eyeballs what's going on in those realms, we tend to forget that it's happening and even if we do remember, that it isn't about us. it's about who we represent.
"And the evil spirit answered and said, Jesus I know, and Paul I know; but who are ye?" (Acts 19:14)
Okay. Assuming you're a Christian and you believe God is real and that Jesus atoned for your sins, making you once again, right with God, and you've had some vestige of personal interaction with them sealing the deal, where do you go from there? Of course the devil's real, we know that too. But just how do we deal with the knowledge that there are those (humans), who by their very nature—opposed to God—allow the mindset of satan to operate through them? Because demonic possession or oppression, even in its subtlest, nigh undetectability, brings with it trains and strains of thought that you must know how to navigate around and unravel in order to simply be and do. In order to live for God in the everyday ways. And as you—a "new creature" in Christ (2 Corinthians 5:17)—now see in stark contrast what you are from what you were, God help you as you wade back into the sea of humanity looking to keep your first love alive.
"But Jesus did not commit Himself unto them, because He knew all men, And needed not that any should testify of man: for He knew what was in man." (John 2:24-25)
Don't let yourself be flattered
The sincerest form? More like the purest strain. I find that the more someone seems to show an inordinate interest in me for no discernible reason, the more likely they are to want something from me. It isn't that I'm a cynic or untrusting. It's more along the lines of a realization that if I didn't receive my sense of purpose and contentment from God, that's exactly what I'd do to obtain the necessary components needed to live a life. And as there are people (God bless their darling hearts) who for whatever reason don't have these things in their life but refuse to "come to the light" (John 3:21) in order to receive them, you have to know that they're out there and they're hungry. Like zombies, shapeshifters, vampires and ninjas (mad scientists too) all rolled into one. People who are so adept at manipulation, you'd never, ever know it unless you had the Holy Spirit pointing it out. Or you were one prior to meeting Jesus.
I'm talking about flattery, plain and simple. In my opinion (and my experience) the opening volley of anyone who is not right with God is flattery. If we as Christians don't realize what we possess in God—a lifeline to Heaven itself—then we've already lost. We're on the inside of ourselves looking out. As a rule, we don't realize how we shine in this world, and this is good. We're not meant to be introspective to the point of self-worship. I will say this though, people see God shining through you, don't doubt it. And the more we interact with Him, the brighter He shines through us. Beware of those who want to take what you have and use it for themselves.
Now, don't you flatter others
This knowledge is not meant to make us feel or be any better than anyone else. Jesus said "But he that is greatest among you shall be your servant." (Matthew 23:11) If you see someone in dire and desperate need of God and His love, pray for them. But if you don't sense anything that says that you should interact with them beyond lifting them before the Lord in your heart, then don't. Your service to them is that prayer, that forgiveness, that mercy. Sometimes ignoring someone is love. You don't have to let yourself be manipulated in order to "turn to him (or her) the other cheek." (Matthew 5:39)
"But when it pleased God, who separated me from my mother's womb, and called me by His grace, To reveal His Son in me, that I might preach Him among the heathen; immediately I conferred not with flesh and blood." (Galatians 1:15-16)