For #2, I've been on the reporting side of the relationship, and I can tell you that the most effective PR folks I've dealt with are the ones who maintain regular contact. (However, a press release is not contact. It's junk mail.) The least effective are the ones who only call when there's a tradeshow coming up, and the ones who bombard me with too many irrelevant press releases. So you've definitely got the right idea.
In GTD terms, I would suggest:
1) Make a regular call, just to chat. Tell the reporter what your clients are working on, ask the reporter what they are looking for. Talk about your cats, their ski vacation, whatever you have in common. Maintain the fiction that you are actually interested in them as a person, not just a source of ink. Monthly is probably too often for this call, every six months is not often enough. Quarterly, maybe? Put it in your tickler file.
2) Keep an @Agenda sheet for the reporter. Add to it as you have ideas that are relevant. Review it at least monthly, probably weekly, and make contact whenever the list is long enough. Send off an email for small ideas, call for big ideas. Don't be a pest: be very very selective about what you pass along. Keep a reference file with each reporter's interests, and review it regularly.
3) Be equally rigorous about managing the relationship with your clients. Just because your client thinks something is newsworthy, that doesn't mean it actually is. You'll add enormous value to both sides if you only pitch reporters when you have real news for them.
Feel free to PM me if you'd like to get into more specific detail.