Start with Bittrex or HitBTC. Bittrex has around 200 altcoins to trade, and hitBTC has lower volume so you will probably be able to trade some ETH pairs. If you're new and you want to daytrade then you should probably trade with like 1% of your account. Look for coins paired with ETH that have high volatility and move in a range. I don't bother spreading between exchanges but then again i only have like 0.20btc. Just customize the scanner to one exchange and you are good to go.