You might buy in to your Ethereum position at $1000, you set your sell position $1300. Your sell order could take days, weeks, months, years or till the end of time to be filled. Once it has been filled, you then take that profit and you roll it over in to a new buy over at, say, $1100. Choosing good targets for your buy and sell orders is crucial if you want to be a successful swing trader but overall swing trading cryptocurrency is pretty easy – set your orders and then just wait.
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.