Google is really the only one to worry about!
Google has a secret algorithm, but common sense seems to prevail. It
certainly factors in the number of linking websites the text content of the page, as well as the qualituy of website construction. I suggest you use Google toolbar which shows page ranking of the sites you visit.
For pay per click, Judicious use of google AdWords is worth loking at - I do this for several clients.
Sometimes I use AltaVista for more complex
searches, e.g. "link:www.lcsc.org.uk" shows a list of websites with
links to the LCSC website - a loose indication of how good the site is.
Sadly, other search engines seem to be getting worse not better. Many are charging
for listing, hence you can't always find what you are looking for and most are
taking many months to register new sites. Most searches in fact use a number of
search databases underneath.
You may want your site registered on these search engines - try looking for
your site with different relevant keywords.
Submitting a new site.
All search engines take time to list your website, sometimes many months even
if you keep on at them, unless of course you are willing to pay.
Free Sites: Google (Dmoz) is based
on a human edited list, submitting sites is free. Altavista, Lycos & HotBot
are free, AskJeeves accepts e-mailed suggestions free. Google and AskJeeves will
let you supply your own short description.
Pay Sites: Yahoo is now $299/year for a business with no guarantee of
a listing. Other sites often charge per keyword and/or per click-through or charge
in the region of $40 to $200 for a simple listing - pricier options are available.
Most use underlying databases that you can pay to be included on, via Overture,
Multiple submission services: No clear figures as to the effectiveness
I have written a short Web Marketing Guide which I can supply for a small fee.