Accessibility Advocacy

Hi all,
I feel a bit silly as somewhat of a newby in these parts, and I haven't been having much luck searching the vast resources available on this site. I would like to contact two developers of apps I've been using, or trying to use, to offer some suggestions for how to make them more accessible in the future. Like most mainstream users, they've probably never even heard of VoiceOver, and I've done my best to describe it succinctly. But how should I tell them what to fix without completely confusing them? I thought maybe I could find some links on this site that explain how to program apps for accessibility. I would very much like to send along this information if only I could find it. Could someone please link to it? Thanks!