Keep in mind, many stocks listed with higher than 15/20% yields could be very risky investments. You can lose your capital if the stock price goes down, thus the dividend payouts may not even get you back to even overall. Don't just pick a high yield stock and expect to get free money every month. There is always a catch.....

Is your strategy for income each month or dividend re-investment to grow capital? The kind of research you'll want to do may depend on your overall strategy.