There are three main categories of income: active income, passive income and portfolio income. Passive income has been a relatively loosely used term in recent years. Colloquially, it’s been used to define money being earned regularly with little or no effort on the part of the person receiving it. Popular types of passive income include real estate, peer-to-peer (P2P) lending and dividend stocks. Proponents of earning passive income tend to be boosters of a work-from-home and be-your-own-boss professional lifestyle. The type of earnings people usually associate with this are gains on stocks, interest, retirement pay, lottery winnings, online work and capital gains. 

One of the easiest ways to increase your passive income is to shift your savings to a bank that pays a higher yield on your savings — for example, Discover Bank and EverBank pay almost 1% for your money. Although it doesn’t sound like much (especially in this low interest environment), little things do add up and eventually interest rates will rise.
Affiliate programs are the current hot thing in monetising websites. The basics are that retailers like Amazon will pay you a percentage if you send someone to their website to buy something. The percentage ranges from around 3% with sites like Amazon all the way up to 60% or even higher for information products sold by other people looking to make passive income. 
Creating passive income is the key to retiring, especially retiring early. If you want to retire early with the stock market you will have to save a huge amount of money, because that money has to last so long and retirement calculators depend on you using your investment to fund your life. With passive income you will have income coming in as long as you own the investment, without every eating away at the principle invested. Creating passive income may take more work than investing in the stock market, but I think it is well worth the extra effort!