There are a lot of ways: Posting ad with adsense, infolinks and others Posting sponsored posts Selling products from amazon
Go to popular search engines and use keyword "earning through blogging" and similar search term will get lots of useful sites packed with earning tips an guidance for making money through Blogging.
I agree. I use Adsense mostly but I have come across blogs that recommend physical products (like clothing, shoes, etc) and then provide a purchase link. They earn through commission.
there are so many ways which in turn will distract our focus. site flipping, affiliate, adsense, etc...............
It depends on what you are blogging about. Do you already have a topic in mind or are you trying to decide on the best niche? If you don't have anything in mind, you need to do some keyword and/or product research to help you decide. Once you know your niche/topic, you can try researching the different methods people have already mentioned above to determine which type of monetization will fit the best.
There are quite a few different ways to earn from a blog.  Banner Sales  Sponsorships  PPC advertising (Adsense etc..)  Affiliate Marketing  Product Promotion  Donations  Blog Flipping
I've seen bloggers who earn using ads and amazon. They are very happy with the result. Yet they need to invest time and effort to make this possible.
Most of the people here seems to be impressed by google adsense or other ad networks but anyone who has a little experience on internet knows that you can earn good amount of money by displaying ads only if you have thousands of visitors on your site.There is no fix formula to monetize your blog different people use different strategies but in my opinion you must experiment with ads,affiliate products and find the ideal balance between different things.The best which i would advise is to develop some of your own products and sell them through your blog .Like you can take best articles from your blog and write some more content and then sell it in the form of an ebook
Sell advertising: This is likely the most common means of leveraging a blog to generate income. If yours happens to become a well-known blog, or one that is well-received in a particular niche, it's always possible to sell ad space on your own. Help sell others' products: Here is another click-through opportunity. Affiliate programs enable your blog to serve as a conduit between readers and online sites offering various goods and services.One popular choice is Amazon.com. If they break out the checkbook or charge card, you get paid as well.
Make a fan page in facebook and twitter it also. Now add a facebook widget in ur blog. Post as much in both places with high quality content. This way traffic will be synchronised both in ur facebook/twiter and blog. NOTE: Quality content can be learned only by practice. Search google keywords and use them more often. This way u'll memorise important keywords.