I would say stick to one project! And put everything you can into it.. and dont be afraid to adapt that project if your visitors are attracted for a certain thing.. Track EVERYTHING.. and find your own niche.. specialise in one thing.. But do it better than anyone else..
I would suggest that one should never rely on just online earnings for living (Except incase you are a freelance designer, writer, Developer etc. ). Education and real Job are the most important. No harm in doing online stuff as a part time. I know there will be many people who work full time online but it may not be advisable for newcomers. One more thing. If you are coming to online earning stuff, Never dream that you will become millionaire in few days. Online earning also requires hard work and dedication. Every niche has its own benefits and demerits. The thing what i hate to do may be earning you a good income. Its all about your interest, dedication and knowledge.
Never believe the guys boasting about their earnings in the Google threads, they are lying and just trying to bait you.
don't just grab any offer there is just because it gives you a huge offer ...make sure its a legitimate work and just like any job you need hardwork,dedication and with the competition,establish your own style...
That's it. In a nutshell. You can't make a real living on the internet. Go to university. Get a real job with benefits, this should be a side thing.
Earning online is similar to earning offline - it takes EFFORT. The cliches are true - if it looks too good to be true.. it probably is, and there is no such thing as a free lunch.