1. The amount of traffic it will generate.

2. The difficulty of getting a top ranking.

The Amount of search volume  it Will Generate:

Often people choose keywords based on how popular they searched. Mostly it is based on “real world” things rather then fact which is readily available. For instance, I recently saw someone who want to go for holidays ,they will just search for holidays or hotels.

The difficulty of getting a top ranking:

If you simply chose the keywords with highest amount of traffic, you could still lose money. This is because these keywords typically warrant a lot more work to rank for. A perfect keyword is one that has a lot of searches but little SEO competition and find easy to rank for. The best tool I have found for this is google adword tool. It will give you an indication of the amount of SEO work required which you can balance against the number of searches.

Some importent thing that is effective for SEO are as follows:

Content:

It has been said that a successful way of establishing a web site is by adding more good unique content to it on a regular basis. It cannot be stressed enough although still people are not doing it and want some “magic” to happen.

Make sure that you have your targetted keywords included in the content on your web pages.My think is that you write without thinking about it and when you finish you can look over the text and add the keyword maybe on one or two places extra where it fits in. If it looks spammy or too much in any way then reduce it.
Always keep in mind before writing content of your web,that you are writing for the visitor and not for the search engines.Also make sure that the text is unique as at all eb pages.there will be no duplicate pages in index.
Factors that are importent in web HTML:

Putting your targetted keyword in places such as the title, H1 and H2, Strong tags and Emphasis tags you put more weight on those words and for the search engines it becomes more effective for those words.But don’t over it because if you place the same word on all the weight tags on the same page you can get hit by the over-optimization penalty which means that basically the search engines figured you tried to cheat them and push you down the rankings.

Navigation View:

You must be sure that the search engine spiders can follow the internal links on your site. If you have a site based on a database it is recommended i.e.  you use mod_rewrite to get the best benefit.
If you have lot of pages on your site and they are buried down in the navigation tree of 3 or more clicks away than I recommend the use of a sitemap and a link to it from each page of your site.

A sitemap makes it easy for search engines to find all your pages and it can also be a great resource for your visitors to find a specific page quickly and redomly.If one or more web pages of your site is more important than the other ones, like the home page, then get more links to it from the other web pages of the site. Home page link will be on each web page for back to your home page. That is also useful for your visitors and it gives more rank to the home page in the search engine rankings.

“The process of finding out the best keywords for a web site and by the use of optimizing the web site along with other off-page work making that web site attain a higher position in the search engine result pages (SERPs) for those selected words.”
Optimization can be done through two ways:
1. On page SEO
2. Off page SEO

The Internet Marketing can help you to increase your business through internet and convert your goals into reality. Internet marketing is an all-inclusive terms for marketing products and services online and like many inclusive terms, Internet marketing means different things to different people. Internet marketing refers to the strategies that are used to market a product or service online. Marketing strategies means that include search engine optimization, online marketing.