Indeed, trading is unpredictable but you can put your risk limit. Chart reading can prevent you to make loss positions , can even give you profit.
Chart reading is pretty basic, the entire cryptocurrency are moving based on the news and speculation, I think you also need to consider that because that is a big factor that might affect the market, the movement is not stable so you cannot just based on the graph because there are more information that would help you to make a right and timely decision, be updated of the current news and events, that's also useful.