Can we collect some good tips for making effective comments on proposed ATF rules? There are no shortage of them coming down the pipe.
Obviously some comments will depend on the relevancy of the rule, such as case law, underlying statutes, and so forth, but in general?
I have found these around the Internet so far, mostly from Washington Gun law.

1.  No inflammatory, vulgar, or hyperbolic statements. Swearing, exaggerating, lying, and generally giving them "what fer" won't help. Even though they deserve it.
2.  Roughly enumerate how many citizens this new rule would impact.  Use "would", not "could".  ATF Rules are not law!
3.  Cost: How much will this cost the taxpayers  to enact, in reality, and is it realistically reflected in the projected costs. (Nothing costs the government anything. It costs us, the taxpayer.)
4.  Ask if this rule can realistically even be effective?  Illustrate how it will inevitably fail to protect the public and likely endanger it even further. This should be simple enough. Everytime they further disarm the law abiding public, they leave them increasingly defenseless against criminals who've never cared about such laws (and others) in the first place.  With our wide open border, this is more legitimate than ever.

What else we got?