Rankings improvement strategy

[EG0CENTRIX]

I am working on my SEO strategies and though it would be good to get advice from awesome members:

1. Our current rankings are on (Google United States) page 5. Our keywords have high competition and hence we need to follow tight plan. I want to learn some best strategies to get Page 1 rankings and how much time would be required approximately. (though I know its weird to ask for time in SEO but what I mean is some case studies or examples of how long you waited when you have pushed your website from page 5 to page 1)

2. What rank maintenance strategies you follow in general. Does anyone have used any agency for rank maintenance for their  niche.

[Impinj]

I read a good post that had a 6 month link-building strategy. Something like this would give you the tight plan you seek to follow. Check it out and let me know if it is helpful: http://www.seomoz.org/blog/the-6-month-link-building-plan-for-an-established-website