» Fill it up.
When it comes to filling your site with content it is no question that self made material - no matter if it is written or a gif image - is better then free stuff from various resources on the web. But if you use them wisely, you can add quite a bit of functionality to your pages - which in turn might attract more visitors.
Choosing to build a site solely on free material is very hard - and gaining a top placement on the search engines might prove impossible - you can make it profitable if you drive traffic to it.
You should try to divide your site into descriptive subcategories or have descriptive names on the files. It makes it so much more manageable for both you, your visitors and the SE bots crawling your pages - In the end, that's what we all want on a web page - Simplicity.
If your site covers many closely related sub topics, it can be wise to see if you can target different search terms on the different areas.
The more content you can fill your site with, the better it will be. As long as you make it easy to navigate and a logical structure - you will attract more visitors and thus make a better profit on your site.
Many people try to make more sites regarding the same topics, writing slightly different texts and targeting different keywords. This might seem like a perfect idea, but the major search engines does not really like it. In fact, they can ban sites they feel has no original content. For free original content, consider using articles.
The best thing to do - is to try to fill your site with as much content as you can - and then move on to the next project - making a name for your self.