You can check out their whitepaper, how large their development staff are, what makes their coin truly unique and valuable. There aren't that many really good coins. Not many with a real community, a developing and contributing community. one that handles all aspects of the coin from promo, graphics, news, public awareness, economic incentives, and continued innovation, etc.
Most of the coins are clones of earlier coins with limited resources, vision and skill
You have to be wise when investing in anything because there is always a price fluctuation and you don't want to be buying something that is at it's all time high. There's a saying in the stock market, "the trend is your friend". If you're interested in trading, learning how to read charts and market mentality are most helpful.