I've backed a few kickstarters for various reasons. One was a well known comic who had come up with a hilarious card game idea but obviously needed funding to make it happen, as their webcomic money was rightly pit back into the webcomic. They got funding in about 2 days and ended up at something ridiculous like 400% funded.
Another one I funded at the other end of the spectrum was a hydroponic fish tank filter. Unknown guys, but know a lot about fishtanks and work in the industry had developed a company aimed at hydroponics. Useful in all sorts of commercial aspects and great for people who want a less chemically tank. They were upfront about how it was designed and they had a prototype etc but the money would be for development and then the tiers were various things with the top few being a full minibars set up with filter etc. Took the poor guys over a year and we'll past their original deadline as manufacturing is a tricky business, especially when you try to be economic friendly and have quite a tricky compression of tank and filter. They kept everyone updated and in a friendly manner, explaining how they underestimated timescales and everything got shipped in the end, international backers getting their stuff a couple of months after. Big success and they recently ran another kickstarter for an even tinier tank aimed at schools to learn about nitrogen cycle, fish, hydroponics etc, with a smaller filter (the first one was pretty damn small and could still do 100gallons an hour). I think they did well, especially with their updates, although they did get slower and slower to update towards the middle but by that point we all understood how hard they were working around their commercial part increasing and their updates got less frequent but longer.
So unless you have an innovative project, are already well known for something, or are fabulous at marketing you have a lot of work to get noticed. I would also say the tiered rewards are essential. You want high medium and low. Your high has to be brilliant, but your medium and low is where you get your money. Low are often just pictures or signed things or badges, and medium tends to be copies of whatever in various forms. My OH is funding a video game and they are almost done with it (about 3 years on) but they have done videos showing dev and their tier levels are brilliant. Dev art, signed dev art, alpha access, beta access, full game, custom skins, various in game bonuses, t-shirts, badges, personalised thank you videos.
Books are harder to ones I find do better are ones with good reward tiers and illustrated books as they tend to offer certain prints as rewards. Lots offer to put your name on their stuff as a thank you, or give you personalised signed copies of whatever they are making. (the card game mentioned earlier did that)
So fabulous idea, but really really needs thinking through and heavily planning pre launch. If you don't make your target you don't get any of the money.