Before starting the article, we need to emphasize one thing to make the picture very clear in front you : Its your writing skill that can make you to Earn Money; provided you can write what the Advertiser wants if you are opting mainly for PPC type Advertising to Earn Money from your Blog.
How Bloggers Earn money from their blog
Writers can earn money online through blogging. Blogger was started in the early 90’s as a way to share thoughts and interests, was used more as a hobby than anything else.
Not all KeyWords has the equal value. Most blogs Earn money in the range of one cent to 30 cent for a click; where as, selected Keywords can fetch $ 4 or more on one click.
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So, in order to earn money, you need to know the value of the Keywords. Understand the difference : you get 100 clicks / day; with 3 cents click value (on average) you can not earn money more than $ 3 /day. But if the value is about $ 1 ? You can earn a huge.
Other direct and indirect ways to make money
In a blog you can promote your own products and services, usually e-books and can earn money. In affiliate marketing traffic to a particular site is driven from another website or email. Advertisers pay to publishers according to the commission schemes. The marketing may be in the form of banners, text ads or reviews of products and services. The reviews can be a simple task for experienced writers.

More you need to know to Earn Money
The Keywords are used by search engines for fetching information. The target audience is very important. The articles that are relevant to them attract a target audience to the blogs. Take your time and makes an effort to analyze what topics interest them.
Above all, a blogger needs to write good content. Success in Blogging depends mainly on the good content. Despite all the Internet marketing strategies those can be used, a blog will fail it do not have good articles.

Thanks for the advise.Value keywords are the way to go.
thank you. :) i very like this article.