I figure that I don't want to talk to the person on the other end of, roughly, 75% of the telephone calls I get in the average workday. I exaggerate, but I point that out to emphasize the nugget of advice I want to put out there, for relatively new attorneys or anyone else, really: return phone calls. It's one of those glaringly obvious things that is said a lot in law school, usually in the context of avoiding grievances. At the same time, it's entirely true.
That isn't to say you need to respond within minutes to the fifteen calls Panicked Client makes on a given day, nor even respond to each individually. Some calls, admittedly, aren't easy to make. I've been cursed, cussed and lambasted for telling people, even my own clients, that they were in the wrong. In the big picture, though, it's better to do it and have it over with than hanging over one's head. Or alternately, if it isn't something you dread, but are just too busy or unwilling, delegate. Quite often I ask the assistant in my office to call Difficult Client and say "Mr. Lawyer saw you had questions for him, could you be more specific so he can work up answers in advance?" In reality, there probably aren't legal questions that need my attention, and the client just wants to rant for a bit.
Contact with opposing counsel is much the same. Yes, Mr. Isnthedisbarredyet is going to rant and rave about your meritless motion and horrible client and allege you're a crook. Yes, Mr. Imtoocheaptohireanassociate will have forgotten why he already called you, with his 1,500 open cases, and Ms. Sixfiguresornothing won't care at all about your matter unless it directly involves the when and where of her 33%. Calling back is, first, just the right thing to do, unless it's a stonewall for strategic reasons. Secondly, there's always the chance of resolution or finding out some new fact/info on the phone. I honestly don't believe I've ever had a case where something relevant didn't come up in these sort of conversations, usually that hadn't been mentioned before. And lastly, it's often quite nice, when the judge asks, to say "Well, your honor, I called him yesterday and blah blah blah is why we can't reach settlement." When the judge wonders why this hasn't yet settled, not returning calls isn't too high on the list of acceptable reasons. There's nothing wrong with calling back to say "I haven't had a chance to talk to my client" or "I'll need more time" or "Can I get back to you this afternoon?" or whatever.
As some of you may have guessed, I spent most of the day waiting for a return phone call. Nothing is worse, as the party who left the message, than the unknown. If our settlement proposal is rejected, I can do something. If it's accepted, I can do something else. If they need more time, I can always wait. Basic civility, even if one doesn't have any human kindness (we are, after all, lawyers) should lead to at least picking up the phone.