Bitcoin can be very profitable.

The most important thing is to stick to one main currency which let you avoid high bitcoin daily movements.

For example my Fiat currency which i use for arbitrage is USD. That means at end of every transactions circle i'm trying to collect all funds at USD account.

Much more profitable is arbitrage with use of two different currencies. Most difficult thing is to avoid high deposit/withdrawal fees. You need to remember that arbitrage usually gives you around 0.5-1.5% if done right way. So you can't pay 1% deposit or withdrawal fees.

Also other thing which you have to look at is Volume. Don't get tricked by medium price. Usually there are many crappy buy/sell orders made by scalping robots.  Remember always buy as many bitcoins as you can sell at same time.

Anyway... that were basics, I don't want to post details here.