1 - Are communications easy, fast and meaningful? That's the first step. Contact more than one supplier (on a initial round, think 10 to 20). Make small challenges like posting design files on a secure site that requires the supplier to create an account...you'll get rid of a lot of unworthy suppliers that won't bother and therefore are not going to be proactive in the future.
2 - Invest in requesting prototypes (or samples if making more than one prototype does not make sense) from more than one factory ahead of time (top 3 of the step above). The good factories will perform well at this task...bad ones will deliver half-baked stuff.
With time, the very good suppliers that really want to build a business relationship with you will become obvious and you can reuse them in the future...making your life easier. Don't be lazy when looking for suppliers...that's the biggest pitfall. Invest time and money...it's important.
I completely agree. As a hardware maker (e-watches) with KS experience (2 campaigns), I find it frustrating that hardware projects on KS start with a negative perception from the public. It seems to me that a track record indicator is missing on KS. Like ebay feedback or a star-rating system...something that people can quickly look at and determine the level of reliability of a returning hardware maker. The number of project created is not enough...it does not speak about level of satisfaction.