Ranger or sin should get flag first, with burst run. Then a tank should get it. The flag carrier should have team with him, unless the flag is getting stolen. Then the team should split, leaving a pom or tos with flag carrier (BS are not enough threat normally speaking to care and just focus flag carrier - no offense to the flag carriers).
The flag carrier needs to b line it back to their team if team is strong. If not a strong team, go to flag room and wait, your team will be joining you soon at res pad.