There are some referees who have made their assistants wear special headsets where a button needs to be pushed in order for what they're saying to be transmitted because a lot of ARs will talk to themselves on the line (I know I do) saying things like "He's good right now, he's good right now, now he's off, he's back on, 6 is holding him on" just to make sure I'm focused. So that is a problem that can be fixed.
Dave, I've said it on another thread and I'll say it again here be very careful about apologizing to players/coaches for your mistakes!!!! It works for Massimo Bussaca and his crew because they're widely known and extremely respected among players (he's among the most respected referees ever, incl. Perluigi Collina) so they accept it because they know he works his arse off and bleeds for football. On the other hand, your players don't really know you, likely don't really respect you (no fault of your own), and probably don't think you put in any extra time at all outside of the 90 minutes that they see you working. It can easily backfire either right then, when they bemoan you for making those mistakes -- a bemoaning you've kinda brought on yourself -- or in the next match they see when they see you and go "uh oh, here comes Mr. Mistakes".