There are certain websites which are trusted among cryptocurrency users. First and my favourite one is coinmarketcap. There you can see charts with price dynamics, top currencies, market capitalization and what happened to the currency in 24 hours. It is extremely useful to see what coin starts growing or falling in price. Poloniex is a site to trade different coins, there are many of them out there. You should also read discussions on this site, they help to get the general idea on peoples' attitude to different currencies.