1) Which cryptocurrencies do you trade?
Bitcoin was general crypto. ICN, ETH, RIPPLE.
2) Which exchanges do you usually work on?
Minor to the Major exchange(Yobit, Bittrex, Kraken, Poloniex)
3) Which strategies do you use in your trades? Does it involve Arbitrage trading? What's the most difficult part of it?
No, just use the standard technique, I think average price in the market for each coin wasn't having a large of gap.