Thanks to high volatility of crypto market and irrationality of markets, futures on bitcoin provide traders with numerous opportunities to arbitrage. All you have to do is to imply a classical strategy with buying the underlying asset and selling the futures.
This short guide from austeritysucks.com explains the process in 6 steps using cryptofacilities trading platform.
1. Buy BTC
2. Deposit BTC to Cryptofacilities and check price
3. Short Bitcoin Futures to lock in the profit at premium price
4. Wait for contract expiration
5. Get back into fiat
You can check their website for more comments and specific examples of making arbitrage profit. They also have an arbitrage calculator which takes into consideration not only spot and futures price but also fees for transactions.