I have great success with indices - I must have misunderstood something?

Hey Guys!
The last days I have had some great success with indices. Because of the high volatility I simply look at what happens in the markets that open first and then go for the same trend when FTSE100 and the other late guys open.

However, I am new with trading indices and I know that it is considered high risk so my question is - can it really be so simple? Is there some kind of danger with this method I does not know about?

Sincerely
PitsofDoom