Update 1st October 2018: The cryptocurrency market has been volatile as ever over the last 6 months. Unless you are a skilled trader, it is harder to make money in a bear market than in a bull market – and we have been in a bear market for some time now. Personally, I have stopped trading and I am now focussing on growing my portfolio passively using a cryptocurrency trading bot – you can find out more about this here. If you are new to crypto, read on!
Always pay attention to Bitcoin. Most altcoins (every cryptocurrency except Bitcoin) are pegged more closely to Bitcoin than Asian currencies were to the USD during the Asian Financial Crisis. If Bitcoin price pump drastically, altcoins price can go down as people try to exit altcoins to ride the BTC profits; inversely, if Bitcoin prices dump drastically, altcoin prices can go down, too, as people exit altcoins to exchange back into fiat. The best times for altcoin growth appear when Bitcoin shows organic growth or decline, or remains stagnant in price.