Smaller weblog traffic is generally created by being active in internet communities (like this one), and by friends and family visiting.
Most people, I think, also get some google traffic. One of the things you'll need to do to attain a higher google ranking is to get linked on other people's web-pages or weblogs. I'm sure you've seen a lot of weblogs that have a collection of linking on them. I think google reads the amount of links coming into a page as a means of 'vouching' for the quality of the page and serving it up higher on it's search results.
I get most of my traffic from repeat visitors and links from other weblogs, though I'm not at all popular.
Trackback and pingback, by different mechanisms, both allow a weblog owner to know who else on the internet has mentioned a specific post of his. If you talk about an entry on someone else's web site, it's a good idea to trackback, because then your page will show up in his comments (or a seperate trackback page), and a few people might follow that to your site.
To trackback, you can usually find a "trackback" url by clicking around. In wordpress weblogs, you can see the 'trackback url' by choosing to view comments. You then copy and paste that in the trackback field and it'll ping it when you post, which just means it'll inform the web site that you're talking about it.
Pingback works in a similiar way, though trackback urls aren't used. You just choose the option, "ping URI's mentioned in this post." If the weblog you're pinging has pingback, you'll show up in the appropriate spot.
I hope that helps.