In order to make money online traffic is all that matters. But traffic does not come by easily without your site being found in search engine results especially in Google.
What i am doing to my e-commerce online store and website is time consuming and a hell lot of work to do. However the good thing is i don't do it all the time, that is only when i am free. In do so i search for any blogs, forums, classified ads or any sites that is related to my blog topic scope and keep their RSS feeds on the browser.
Every time the sites are updated with new topics, i will go directly to that specific topic via the RSS feed update and post my comments. Of course this will not help your blog ranking to increase over night. However with perseverance and patience your effort will be paid off over time.