(1) Search about the company in Google
(2) Ask for examples of websites they have optimized for reference purpose
(3) Check out the page rank (PR) of their own site
(4) Judge their response time
(5) Get recommendation from your friends, business partners etc
(6) Find out how they do the backlinking
(7) Ask for the monthly ranking Report

[1] Avoid JavaScript menu

Search Engines can not simple understand the JavaScript and they ignore the content & hyperlinks in it.Suggestion is to use HTML hyperlinks and become search engines friend.

[2] Avoid Optimization of Homepage Only

In addition to the home page optimization, inner pages should also be cared for and should be optimized which helps in getting search engine traffic.

[3] Avoid dynamic pages

Search Engine Can not understand dynamic pages which has session ID ( it has “?”  character with different parameters) .Suggestion is to avoid URL with session ID and if it is not possible than use few parameters only to become search engine friendly .

[4] Avoid Neglecting Interlink Structure

Often we neglect the interlink structure of web site and always spend too much time on home page and in too much link building .Suggestion is to use the interlinking structure which can enhance search engine rankings for all important web pages.It also helps in distributing link popularity efficiently.

[5] Avoid Unethical SEO Company

Be careful while dealing with SEO companies who follow an unethical & black hat techniques ( such as hidden link, content copying, link farming etc ) to achieve ranking overnight .These practices can put your web site out of gear and your web site can be banned .Suggestion is to avoid such companies who sell the dreams for their short gains.Choose an practical SEO company with transparent working system.

What really happens is Google sends out spiders to crawl the Internet, usually done to DNS (Domain Name Servers), upon spidering all of the available tables it begins to go through each individual site and updates the content on to Google.com. Thus if you watch your rank on the Google Toolbar, you can tell when your overall page rank has changed.

Understanding SEO and what is necessary to improve your overall ranking. Webmasters have been looking for ways to increase the odds of guessing when the next spidering would commence. There are various versions and servers that go out and crawl thousands of servers at a time, it takes time to relay and interpret this information back to the web server that Google.com pulls its information from.

Some vendors have created programs that actually go out to the data centers themselves to find out approximately when the last index was kicked off. Depending on the information returned from the trace the exact time and date are pinpointed. Is there really that much of an advantage to doing it this way? It depends, if you have a vital update that you want to optimize your site, you may want to know when the last time Google visited your site for content to keep information fresh and relevant.

There are many data centers that Google uses to spider across the world. Each center has a specific region it covers and all the information is gathered in aggregate and returned back to populate Google.com. With this many data centers the chances for continuous indexing is good, but not guaranteed.

Now if you’ve been a keen Google fan you’ll know that they have 3 main www servers online, which are as follows:

www.google.com - The main address, the true homepage of Google.
www2.google.com - Thought to be a test server.
www3.google.com - Thought to be a test server.

Whilst nobody outside of “Google” truly seems to know the purpose of the www2 & www3 servers, many people have come to the assumption that they are test servers. During the update, which takes several days, the 3 Google servers display different results. Whilst the results vary from server to server, they are said to be “dancing”, hence the name “Google Dance”.