Yes, if you want to do internet related work then there are many...
you can do freelancing
you can do link building
you can do blogging
you can target Adsense only
you can build websites/ebooks based on ClickBank
you can do forum marketing and lot more other works as well.
What I have learned is never give up, keep learning and keep doing whatever you are doing on internet but do legitimate work, try to broaden your thinking power, think if you are in the work, other people are also there, is there any money, is there any value of the work which you are doing, does society would be benefited from your work?????
If you think of Google then you would find that Google is mainly helping the society first then businessmen, same logic you have to apply in your work also....
Apart from all these, discipline, time management, understanding of internet community, communication skills, creativity, knowledge of latest technology, focus, quality are very important in online marketing....