I guess you are referring to the pats, patrols, they have a set pattern that they walk along, past and through other mobs.
The trick here is to observe their movements as you approach, if you are in a very difficult area this could take time.
Choose a time when they are either away from other mobs, and take them down alone, or wait until they are near only one group, then sleep, concuss, whirlwind or otherwise incapacitate them, take down the group, then take them down after.
Unless I have been trying to solo a heroic area I have not found the pats to be a problem in this game. If you are talking about heroic areas then you are going to have an extremely difficult time unless you are too high level for the area. The only exception I have encountered where soloing a heroic is fairly easy, with a companion, is on starter planets.