Buy the rumors and sell the news means buy it when its still unconfirmed and sell it when the developers,or news confirmed it.
Basically that's what most of the expert traders usually say. The news also can be a big trigger sometimes in the market, that is also you need to keep in touch and keep updates about the news, upcoming events about that, most especially when there is a news in one specific coin, you should also watch out the news of bitcoin, surely it will have a great effect when you are trading.