The first step is determining if an investment is interest-based or profit-based. Some common interest-based products are fixed-income, GICs, Bonds, and Debentures. If you hear these words it means you are lending someone money and getting interest in return. Run!
On the other hand, Profit-based investments are fine to invest in. Dividends, Stocks and Equity are all terms that can be associated with profit. If you hear these words, you can move on to the next step.