This is a common question in the pursuit of more money.  The answer depends on how much startup money you have and what interests you the most.

If you don’t have much money to invest, I would start with making money on the Internet.  Even if you do not have any web skills and want to put up a website, you can have it designed and hosted for under $700. 

If you want to be an affiliate for companies, you can start with as little as $10 per day and see how you do.  Becoming an affiliate and using Google AdWords is probably the easiest and cheapest way to ease into making money on the Internet.  Be sure to do your homework and you will pick it up quickly. 

Once AdWords start making you money, you can use it to build a web site.  Now you will have two new income sources, neither of which will require a lot of your spare time.

If you are not interested in the Internet, you should consider going into stocks.  You can start off with a few thousand dollars, and you might want to begin with a well-known stock picking service.  You can also subscribe to periodicals such as Barron’s or Investor’s Business Daily to get up-to-date information.

Another option is to stick with real estate — many wealthy people made their fortunes this way.  Anyone who has bought and sold a home is already familiar with the process, and it’s even easier when you don’t have emotional ties to the transaction since you are not buying it as your home.

There are numerous books and products on real estate, stock investing, and making money on the Internet. In fact, there are many books on making money in general.  But be sure to research books before you buy . Some don’t give examples on what to do, instead giving background information and different philosophies on investing. Read reviews and newsgroups to get the inside scoop.