The frequency would vary and not very predictable. I have noticed some pages being crawled twice a week, while some get attention only once a month!! cheers
Yours is a brand new site I assume. Use a sitemap- it will be easier for Google to find those pages of yours.
Submit Google sitemap, it will index your site regularly also it will update the facts, whatever happen in the webmaster category.
Depends what you mean by re-index but if you are meaning "index" then it swings wildly and is dependent on many factors such as inbound links and frequency of new content. If it is a new site then expect pages to drop on and off the index for a few weeks.
first thing create html site map of your website, second xml site map and submit in Google and third use h1 tags for headings and improve keywords density in content