joined:July 21, 2012
some say that when you create new content you should rank within a few days some says like you that google has to re-evaluate everything and that is can take a few weeks, who is right I don't know
A new page is a different issue, it didn't exist before so it goes straight into the evaluation process. New pages can rank very well very quickly (in minutes if it's on a major news site or a popular forum like this, but for most average sites it will take a few days) and rankings will fluctuate until it finds a final resting point.
An existing page has been evaluated previously so tweaks to content are unlikely to produce any significant ranking changes. It can happen but in my experience once a page is established it takes a major change to improve ranking, and usually only links or linking to it from your home page are likely to produce a significant difference.
The thing that I know is that without being signed in after 72 hours the page in question was ranking where it has never ranked before ( it stayed there for a while, then I cleared my cache and it was gone )
Did I get lucky and will it come back where I saw it weeks from now not sure…
The rankings you saw were local/personalised, not 'real'. Clearing your cache removed any personalisation. I've become excited on many an occasion and been baffled by the lack of extra traffic only to discover it was only me seeing the ranking change.
Or in order to rank will I need external links ?
If the page doesn't already rank and you're changing the content to get it to rank, there may be some other problem with your site as a whole. For example, sites severely affected by Panda or Penguin can struggle to get any new or existing pages to rank no matter what they do.
On long term key phrase If I take 8 or 10 words from my page content it find the pages and ranks it but on shorter terms like 3 words that it where it doesn't rank it.
Either your site or the page in question does not have sufficient authority/trust to rank for anything other than long tail phrases.
I am curious what is the best to check your trust ? majesticseo or moz ?
I find Moz a good enough indication. Other tools may be more accurate/reliable but Moz will give you a very good idea how your site compares to others you're competing against in terms of trust/authority.