Hello and Welcome! My first rule of investing would have to be, make sure you understand the business you are planning on investing in. Watch for trends. Hope to see ya around!
I think you definitely should try to investigate the stocks of companies that you're interested in. The fundamentals of business are relatively easy to learn and if you have an idea of business basics, you have a great understanding of how companies are valued. And try to steer clear of hype. There's way too much of it with most stocks.
So how's life treating you?