The edge institutional traders have over retail traders, just the same as if one was a stockbroker (institutional vs retail players) (I was once an institutional dealer in a major stockbroking house :-)) or an inter-bank forex dealer.
Institutional guys have much more advantages, namely ready and easy access to lots of capital (I had access to over $10m a day), and we don't have to pay brokerage/commissions/spreads. Commissions in stocks or spreads in FX alone can kill you.
We also have lots of back room support. Research, analysts, all sorts of goodies. And most importantly the network of associates in other firms, etc. Just like a forum but we have access to stuff most investors don't but that does not necessary mean it is 100% accurate. It's just an edge.
Having said that, let me assure you that with all that, the pressure is very high and burn out rate is high. In my opinion, given the amount of capital I now trade privately vs money thrown at me as an institutional dealer, I prefer it now as I get much better return on equity and very much less stress. Most times, capacity ($$$) can actually work against you. Ask Warren Buffet.
There is no grail. Just be sensible and disciplined. That's it. Hope that helps.