Tal the time to do Kickstarter is really when you are at pre-production for your development. Kickstarter policy is very clear on physical product and that is that if you are offering product as a reward you should have a demonstrable working prototype. This is in response to a number of high profile raises where the funds evaporated and the product never appeared.
I wouldn't worry so much about the average Kickstarter raise as there are a broad range of products/projects and media events promoted. If $684 was really the average raise then nothing would be funded as they would fail their minimum target. The good projects get funded. I helped fund a couple of hardware projects and a graphic novel and all exceeded their targets.
The onus is on you to connect with your audience, get PR at the right time (just as your Kickstarter launches) and engage viewers with your project. The parameters are very simple. Explain what you are doing and why, who you are and why this project changes the game in some way. The effort you put into social media marketing ahead of the Kickstarter launch will pay dividends in the end.
If you try and raise for an idea you will fail, assuming your project gets accepted at all. De minimum is a working prototype and an idea of what it will look like. Craft your offerings to make sense, with limited version options if you can so that you can cap the number of backers. Keep your project updated and use video as much as you can. Good luck!