In a long and sometimes personal letter, I was asked what boiled down to these three fundamental questions about belief.
How can you achieve what's proven to be an elusive faith in God (especially in light of all the terribly difficult times you've lived through)?
How can you take religion seriously if it's so often used as an excuse for cruelty and evil?
Why should you believe in a book written, in part at least, by a "human hand"?
Let me work backwards:
I agree with you completely: if the written Torah is even partly of human origin then we are doing ourselves no service by believing. A book that claims to have been written entirely by Moses "taking dictation" from God (see Deut. 31; 24), but which was instead a compilation containing human observations and agendas is a fraud and has no place on my shelf. The Torah ONLY has value of any sort (beyond the poetic) if it's exactly what it clearly claims to be: Divine.
I believe that serious evidence exists to support the Torah's claim of Divinity (among the best examples is an e-book written by Rabbi D. Gottlieb). Either way, though, a thinking Jew has to face the question that you've asked. For many people, this experience can also be a strong first step to faith.
That religion is sometimes used to justify vile behavior is an undeniable truth. But you can't necessarily judge Judaism (or any religion) by its adherents' behavior. Judaism should stand or fall on its own qualities, independent of flawed or even failed followers. I'll admit that if corruption and abuse were widespread among observant Jews then one might wonder if there was something wrong with the message. But my own experiences and the limited statistical data that exist suggest that, on the contrary, Judaism seems (with exceptions made no less tragic by their relatively small numbers) to have delivered stable and nurturing communities and families.
But how to acquire faith: that's the million dollar question. I'm sure you won't be surprised to hear that there's no easy five-step process that's guaranteed to generate full and blissful faith. If there was, and if I were in on the secret, I would probably already have made my fortune writing the "Idiot's Guide..." Indeed, one might think of faith as a precious crystal vase; difficult to acquire, beautiful to have but awfully easy to break.
Let me suggest two things, though:
open-minded and wide-awake investigation, discussion and debate about fundamental issues of faith (without knowing you, I could imagine a list including questions surrounding origins of the universe and of life, authenticity of the revelation and transmission of the Torah, suffering and G-d and perhaps the Torah and women's issues). Your community might have classes or individuals that welcome stimulating challenge and that refuse no honestly asked questions...no matter how pointed. It would seem to me that this is a process that could serve to help clarify many issues. And the clarity alone is probably worth the effort.
Intelligent mitzvah-observance. Very briefly, while the Torah's commandments each have their own intrinsic value, they are also symbols of Torah attitudes and wonderful windows opening onto the deep and full beauty of a Torah-lifestyle. And, yes, of faith. Habitual observance won't yield even a tiny fraction of the profound understanding and goodness that are available in a mitzvah. I'm confident that this much you already know.
So why not choose a mitzvah for a given period of time (a week?) that you'll perform with all your energy and attention. It doesn't have to take long, but if you're "awake," you'll profit. I might suggest prayer as the first experiment. The traditional prayer book is an unequalled treasure house of thoughtful, yet strangely puzzling ideas. Take, for instance, five full, quiet minutes to read the three paragraphs of the Shema. Make note of the questions raised by the words (I bet you won't find less than twenty!) and imagine yourself actually speaking these words to a G-d who's listening....
As I said, this isn't a guaranteed or instant process, but it's a first step and first steps do tend to lead to second steps. If you like you can let me know how things are going and tell me if I can be of any help.