Blogging should be for fun, else you’ll quit easily. The only thing that motivated me to have own blog is just to exchange my ideas and experience with other people with similar interest.
The toughest part is to get the traffic. A blog without reasonable readership will never generate any income. I guess high traffic is the crucial, so search engine optimisation is needed, do some marketing and promotion to increase your blog’s presence. There’s ton’s of ways to make money but if you do not have the rights tools, you’re just spinning your wheels.
I have global advertising ads on my site like AdSense, but rarely readers click on it. Many bloggers are likely to take advantage of such Advertising Programs to earn a profitable income. But Google has it own strict policies; it will ban people for invalid clicks, which is highly frustrating. I think it is best to do more research on other advertising media, like Bitvertiser, Adbrite, Chitika, Ebay Auction Ads etc to suit your needs.