Meta Tags are a Big part of it.

you need to pay to be at the top or just be a popular site that everyone goes to

Can’t remember where I seen it, but as far as google works, they look at how long you registered the domain. If the domain has only been registered for a year, usually they won’t list the link.

I’ve also found out the meta tags don’t mean much, but your title does. I try to make page titles with few words that are relative to the content. Forums & blogs seem to be picked up the most, and don’t need any advertising. I’ve got a couple of private blogs (not password protected), but not publicly listed, but somehow they found it, and google has a great deal many pages in that forum linked.

Some web hosting softwares have it so you can block search engine spiders. I would not block any spiders from searching your site.

Another way is if someone searches for a topic, and they keep clicking on your link, it will keep moving up the list. The most clicked links get the most attention. This is why it’s important that your title page closely match what someone would type into a search engine.

I never had any luck with the free submission engines.