After reaching the #1 spot with everything you did to reach that spot, lets say 3 months down the line - what would need to be done for the SAME keyword phrase monthly? Even though you got some pr5-9 perm links and so on, what would YOU do to keep that #1 position per month to make SURE you STAY #1?
Content. You want to make sure the page is interesting enough to attract natural traffic so that you don't have to work as hard to retain the rank. Some sort of automated system to draw traffic like affiliate system or link ranking system.
If I had a URL that was #1 for it's targeted keyword phrase(s) then I would not touch the content on the page. I wouldn't change <title>, <h1>, or anything. I would simply continue to build back links to the URL with my targeted keyword phrase(s).
you have to keep building backlinks on an occational basis to maintain the ranking. cause while you are at confort zone reaching #1, your competitors are not resting and they are building links. if you stop building links, you will fall behind over time
Start building content on other pages on sub topics of your major key phrase. Then start doing some link building for those pages. Strengthen your "theme" with Google and it will help you keep #1 key phrase at the top.
Just continue what you've been doing. Build quality links. That's the only way to get a stable ranking.
If I have that site being in the top spot, I'll just continue what I'm doing Changes of any stuffs in my websites could affect its ranking, and you don't want that to happen right?
I wouldn't change any of your structure stuff like headings but definitely keep adding fresh, relevant content if possible and building backlinks. If you continue to do this you should keep ahead of the competition and keep things interesting for visitors which will naturally attract them to come back and give you backlinks from their blogs/sites.