Market makers obviously operate in very short time frames, so those sorts of bank traders do. In terms of more “discretionary” types, some definitely do.
[B]After getting into a position[/B], which of the following is a good practice …
(a) look for more opportunities.
(b) concentrate on existing position only and manage that …only look for other opportunities when existing position is closed.
Depends on the time frame in question and the correlation between the pairs you may be looking to trade as additional positions. In the short term you probably want to focus on just the current position. Longer term you can get away with having more on because there’s less specific focus required. You’ll want to avoid adding a correlated pair in either case because you’re essentially just increasing your risk.
Yes in my view they do trade in the smaller time frames as it provides them with the lot of opportunities for hedging. Well regarding to your second question, you should not only concentrate on your existing position and manage it effectively, infact you must look for more opportunities as well. It also depends on the strategies of different traders.