It's possible for a solo person to easily make that and much much more. I'm a solo affiliate marketer (though I do outsource some contract work such as script implementation, link checking, specialty graphics, etc.) and affiliate marketing is the sole source of income for my family. And we live quite well. ;)

For starters, I would recommend avoiding pay per click and pay per lead campaigns. These programs have their place, but until you get some experience under your belt, it is difficult to discern which are worth your time and which are not.

I would also recommend joining Commission Junction. http://www.cj.com/ -- they are one of the best networks for finding merchants to promote, and IMO, the very best for people new to affiliate marketing.

The toughest hurdle for new people to overcome, IMO, is that you have to focus on selling products, not providing free content or services. Take it from an old time content provider, you've got to spend some time learning what people are looking to BUY (not read, download, or get for free) and then show them the best places to buy it.

http://www.wordtracker.com

WordTracker is invaluable for learning exactly what people are looking to buy. I don't make a move without it.

As Catalyst says, SEO is critical. For most Affiliate Marketers, free search engine traffic is a huge source of their buying traffic. If you don't learn SEO, plan to spend a goodly bit of your income on advertising.

However, while good SEO is critical and an excellent start-up strategy, the Search Engines are extremely volatile and free SE traffic should not be your ONLY source of traffic for the long term. Once you're generating a decent income from SEO (or even before), you want to look at long term goals and how you will get repeat visitors to YOUR site (not the merchants).

What makes your site worthy of a bookmark?

It may not sound important when you're doing well in the SEs, but TRUST me, you'll understand the value on the day google belches and your sites end up missing (even when you've done nothing to "spam" the search engine). Yes, I DO speak from experience. ;)

For beginner affiliates, I also recommend avoiding Amazon -- there's much too much competition. Additionally, they do NOT have the best affiliate terms (commission, length of cookie, quarterly payments), so it takes some experience to know when it will be profitable to promote them over merchants with better programs.