What is needed to have a strong, impactful resume?

Really good tips, let me add the "so what" factor for the entire thing. Ask yourself so what? Here's a very simplified example: I attended a conference. After asking "So what?" Perhaps you change it to " I enabled five new multi-million dollar accounts to be opened after following up with key accounts during the XYZ Conference. This simple test helps to show the value provided in everything on the resume. It helps keep it streamlined, focused and to the point. It's a lot more work, but really worth it.

How far back do you include your work history? I've worked at PSU for 25+ years in a variety of positions. Then I had positions in advertising and banking prior to that (not in any sort of PM role or tasks). I had to really work towards this role. So as an older job seeker, where do I stop listing history? Right now, I've stripped out most of it from the resume and only have the past 3 positions at PSU. I think it goes back to the year 2000.

How far back do you include your work history? I've worked at PSU for 25+ years in a variety of positions. Then I had positions in advertising and banking prior to that (not in any sort of PM role or tasks). I had to really work towards this role. So as an older job seeker, where do I stop listing history? Right now, I've stripped out most of it from the resume and only have the past 3 positions at PSU. I think it goes back to the year 2000.

That depends. For federal resumes, some positions require 15 years or more-rare but it does happen.
For the private sector, 5 years is great. 10 is ok.
My suggestion would be to have a professional resume writer write your CV, since this is clearly the case where a pro would be most beneficial.

Great notes and great topic. To add to the above, I believe you should consider two things mainly:
1. Thé length of your CV. Like any other document, Employers may get board going throw long resume and decide to skip some of the important achievements that you have mentioned in your CV. Hence, try to make it as short as possible focusing only on major achievement.
2. I have seen a lot of CV starts by the section "Career Objective". If you are some one who has some major experience in his/her field, I believe the title of this section should be changed to "Career Profile" as the word objective may indicate a lack of in-depth experience.

Really good tips, let me add the "so what" factor for the entire thing. Ask yourself so what? Here's a very simplified example: I attended a conference. After asking "So what?" Perhaps you change it to " I enabled five new multi-million dollar accounts to be opened after following up with key accounts during the XYZ Conference. This simple test helps to show the value provided in everything on the resume. It helps keep it streamlined, focused and to the point. It's a lot more work, but really worth it.