The following answers represent "shooting from the hip" from a Christian. And I'm an old woman, to boot -- Aren't we old-women the universally acknowledged wisdom keepers? As John Wayne might have said, "All right, pilgrim, listen and listen tight..." (If that doesn't work, how about "Lock and load"? "Circle the wagons"?)
I'm too close to the finish line to play other peoples' games. I've already wasted too many years trying. I don't recommend it.
I know that I am a Christian because I know that I am a Christian. That's what counts, IMO. I had my first "real" (not forced) subjective Christian experience over 22 years ago, at a time when my stated belief was universalist. I now consider myself a Christian universalist -- I understand that other people subjectively comprehend a different face of God than I do, including many (most) other Christians.
I encourage others to strengthen their own heart-felt perception of God, even if that is, as it is with many atheists, simply the face of humanity instead of a supernatural being. Reference Matthew ch. 25, the final judgment, sheep and goats: sheep are known by a life of feeding the hungry, caring for the poor, etc., "as you did for the least of these, so you did unto me." Compare with the New Testament teachings about blaspheming the Son or the Father, which can be forgiven, as opposed to blaspheming the Holy Spirit. Who encourages men toward compassion and kind "works" if not the Holy Spirit?
I subjectively believe that I have a real, true relationship with Christ, Mary, and the Archangel Michael (my unorthodox personal trinity). It would not be possible for me to reject the person of Jesus or His teachings. It would not be possible for me to live any way other than MY understanding of Christ's teachings. The first scripture verse I ever truly "got" is found in I John: "God is Love". Perhaps that remains the only scripture verse about which I feel confident in saying "I have understanding." It is enough.
How one asserts, or lives, new-born Christianity: act naturally? Like Francis of Assisi when he ran out and hugged a leper? You are becoming a changed person -- why behave like someone else? Or even worse, like someone else's idea of how you should behave? Listen to that "still, small voice", trust your intuitions. Trust that God is not a mischievous practical joker -- at least not in matters of consequence. He is not going to make Himself known to you, reach down, lift you up, then drop you on your head and walk away laughing.
If this happens to you, well, it wasn't the voice of the God of Christ you heard, anyway. I'm pretty sure on that point. I'm also pretty sure that if you inadvertently followed the wrong voice, and you ended up being dropped on your head, your child-like willingness to follow that voice created a sufficient opening for the God of Christ to reach down and offer His hand to you for a rescue. This "insight" comes from first hand experience.
I can't speak for others, but I certainly didn't come out of my early religious experiences with a PhD in Theology from The Divine University of God. I got the general idea, but was "off" on some of the details. I'm probably still "off" on some details. That doesn't stop me from trying, from living according to my beliefs.
Re: commitment. How is "I'll give it a try" -- living according to your intuitive faith, perhaps your understanding of love in action, perhaps your understanding of Christ, simply following the dictates of your own heart -- an overwhelming commitment? What is the alternative? How else would you live? If your understanding of commitment seems overwhelming, are you thinking of someone else's dogma on the meaning of commitment?
Re: professing Jesus: "Christ" is my own common personal name for the spirit of Jesus and the God of the New Testament. I refer to Jesus of Nazareth as the fully human vehicle for the teachings of Christ. Emphasize "fully human". Scripture says He was without sin, not without common human foibles. You think He never once tripped over his own sandal? I really want to make a video, "Bloopers of Jesus" -- maybe followed by "Bloopers of Mohammed" -- followed by "Fatwa Follies".... Oops, Did I go too far? My personal vision of God includes a sense of humor. Humor, IMO, is a terrific tool for uncovering truth, combined with a joyful spirit -- why should we fear truth or shun joy?
What happened to your cleric friend is horrible. I don't know many Muslims, and I cannot imagine what kind of God he knew who would lead him to such a dark place. I have known some Christians whose dogmatic perspective seemed, to me, too closed, with no room for growth, for adaptation (the Apostle Paul's being "all things to all men"). It is sad that your friend didn't feel he had the right or freedom to take a back-step and re-examine his beliefs. How did such an apparently good and wise person get backed into a corner by such a rigid, malevolent vision of God? As you are able, I'd like to learn more about your friend and what you think happened there.
Bridging the gap with other Christians -- my experience would advise that, as much as you can, you should meet them wherever they are, and lead by example. Again, referencing Paul's "being all things to all men". Never hate, condemn, or promote any form of meanspiritedness. Be always loving, forgiving, merciful, kind, gentle, as much as you are able. Even if they seem misguided, in your opinion (and probably in mine), they are not evil. Think of this: when they get to heaven, as I believe most people will, they're in for a real shock when they see how many other people made it, too!
I'm no longer active in church (I'm old and live way out in the middle of nowhere), although I'd have no problem returning to the church of my youth (Episcopal). I guess now I really belong to something and someone else, and my fellow parishoners are (loosely speaking) the rest of God's creation.
For inspiration beyond the New Testament, I personally find strength in reading some of the very early, non-canonical but widely accepted church literature, such as I Clement, the Odes of Solomon, the Epistle of Barnabus. I read about "saintly" people who touch my heart, who give me a model to emulate -- like Francis of Assisi.
In addition to wasting a lot of time trying to fit someone else's idea of being Christian, I've also been guilty of, and still am often guilty of, spending too much time and angst trying to understand things which can only be learned through first-hand experience, diving into the pool of the Christian life.
"Winging it", when not thoroughly prepared, is a little frightening at first. Still, once you realize that you're not going to turn into a pillar of salt, even if you make a fool of yourself occasionally, you begin to understand "living life abundantly". We humans tend to "err on the side of caution" -- maybe sometimes it's better to "err on the side of non-caution"?