The more pages (or blog posts) you have, the more likely it is that one of them will show up in Google, when someone searches. Each new page will draw in its own small stream of visitors from Google, and may even be linked to by other sites.
There's not a huge amount to say about writing content, but for an information site, it's the thing you need to spend the most time on.
Writing content is also important from a quality angle. For most sites, it's not just the quality of the content you have, but how much of it there is. You should aim to create a site that is a significant and comprehensive resource.
If you write content on a regular basis, people will come back, and become frequent visitors.
Copying content is a big no-no. Google sees this, and will only rank the original page highly in its search results.