Finding a title for your book is tough. So many possibilities! I have time to come up with mine still because I'm maybe 40% into my first draft, but the issue continues to vex me.
Yes, I used the word "vex." I like it. Sue me.
One strategy I use is to find cool quotes that deal with themes or issues in the book. I'm considering using such quotes at the top of each chapter, or maybe just one quote at the beginning of the book. Regardless, sometimes the quote has a phrase in it that makes a nice title. Shakespeare and the Bible have been pillaged for book titles - Something Wicked This Way Comes springs to mind, but there are dozens more.
I recall a line from an Aeschylus play: "Still there drips in sleep against the mind/Grief of memory." I always liked "Grief of Memory" as a phrase but have yet to come up with an idea where it's an appropriate title. An obscure eighties song had some lyrics: "I met the devil at a party/we played power games./He out-sinistered me severely/I had to look away." Not great lyrics, but I love the pseudo word "out-sinistered." Not sure how that might be used in a title, but juicy words like Sinister and Nefarious often make good title fodder. But then I like turning odd nouns into verbs like that as well.
Thesauri are useful for titling. As is surfing Amazon.com and seeing what titles others in your genre (or other genres) have used. See what works for you and what doesn't. Come up with a huge list, then begin to whittle.
Say the titles out loud. This often weeds out the silly ones that might past muster if you only read them in your head. In fact, try reading all your fiction out loud to yourself. It's a great way to see what works and what doesn't.