Ask HN: Sources to help determine where to invest?

I'm in the fortunate position where I have approximately $300 surplus/month. I found a brokerage which allows me to buy stocks/ETFs fractionally, based on dollar amounts as opposed to whole shares, and I'm seeking reliable sources of investment advice. How/where do you learn which companies are up to what? Obvious choices are Apple & Google, but I'm interested in learning who else might have good stuff up their sleeve.