Sometimes your audition consists of reading with others from small scripts called "sides".  These may be from the play being cast, or from other sources.  There may be a choice of sides, depending on the parts you might be auditioning for, or the auditors may distribute them as they see fit.  You may get to see them in advance, or be handed one and expected to read cold.

You might read with other actors who are auditioning (most likely), or who are not but are helping out the director as a favor. You may read with crew members or friends who aren't really actors themselves, just involved off-stage somehow.  It really is a different event from the monologue audition and has some different rules.

I've read onstage with actors (experienced and not), stage managers sitting in chairs, friends of the director, even the assistant to the assistant director's assistant's co-assistant in training.  Some of them read so well I briefly felt inadequate; some so badly I got nothing to work off and didn't feel myself that I read very well.  In one instance, I unfortunately focused on how little the other reader contributed to the process. I had received the sides in advance of the audition so I was well-prepared.  However, I had "imagined" how my reading partner would do his part, and anticipated that in my rehearsed responses.  Only he didn't apparently work the same way!

It goes to one point in general that applies here particularly:  be ready for anything.  Be flexible, be adaptable, ready to adjust to the moment.  You just never know.

There's another point to be learned from that last episode that applies to auditions as well as rehearsals and performances.  When you're rehearsing, don't project onto the other actors a specific performance; don't assign them line readings in your head.  They're going to do what they do, and part of what being an actor is all about is "re-acting", and it helps if you pay attention to your acting partners, listen to what they say and how they say it, no matter how badly they do it, and respond to it in character.

So, how about a short list of tips that might help get you started.  Here are some things to keep in mind for the side-reading audition.  Also check out my tips on Monologue Auditions.  Many of them apply here as well.

1. It bears repeating:  Warm up before your turn, vocally and physically.  Ever hear an orchestra just before they start?  Ever see a sprinter practice jumping out of the blocks just before the starting gun?  If you think it's a waste of time, consider what performer (artistic, athletic, etc) ever skips this step prior to their performance.  If you can think of one, please let me know.  Until then, warm up.

2. If you can, get a copy of the material you'll be reading from.  Don't worry about memorizing it, that's not expected of you.  Don't even worry about rehearsing it.  Scan it for unfamiliar or difficult words.  If you're familiar with them, practice saying them.  If you aren't familiar with them (and hopefully there's only one or two) ask just before you get started for help in pronouncing them.  Don't be afraid to, no one is grading you on your vocabulary.  If you aren't allowed time to pre-read it, ask for just a moment to scan it over and see if there's any words that might trip you up.

3. Get a handle on the character, but not too much.  You might ask for some brief insight into the character before you get started, although often the director will offer something like "Gus is a bully, but misunderstood", or "Mary came off the streets and is pretending to be royalty".  Just enough to work with on short notice.  They aren't expecting full-blown characterizations at this point, but a little can go a long way.

4. Sometimes the director will ask that you simply stand still and read.  They may suggest you move as you feel appropriate.  Keep any movement to a minimum.  Don't make it hard for the auditors to watch you by running all around.  They want to see you and hear you.  If you've walked into the audition under your own power, they'll assume you can move when and where they need you to.  You also don't want to throw off your reading partner bounding around in and out of sight.

5. The auditors will probably tell you where to start reading and where to read to.  If not, ask.  When you get to that spot, stop.  They may not tell you to, as they're thinking, conferring, or making notes.  It just wastes time if you keep reading beyond what they want to hear.

6. Here's one of my favorite tips:  pay attention to the last line to be read.  If it's yours, make sure you are ready for it, especially if it has impact.  Rather than stumbling over it, deliver it with authority and appropriate weight, and you can only do that if you're prepared.

7. Here's another favorite tip.  Story time again.  One time, at callbacks, a dozen of us were taking turns pairing up to read for eight roles.  It was a round-robin, with the director asking for different groupings of us to the stage to read.  After we read, unlike some of the others, I did not walk off stage and toss my script onto the table and take a seat in the dark.  I stayed on-stage, script in hand, attentive, in view, not chatting, giving my attention to the director.  And when he looked up to see who was around here and there, and I caught his eye, I gave him a look that said not "do you still want me up here" but rather "what part shall I read for now".  I started reading in the second grouping, and never left the stage until it was over.  Truth.  And yes, I was cast.  Act like you're supposed to be cast.  Can't hurt.

8. Some courtesy issues that shouldn't need mentioning, but from experience I can tell you sadly that isn't the case.
   a) If you aren't on stage reading, sit down and shut up.  If you must get up for any reason, do not cross between the director and the stage while others are reading.  If you feel you must chat with a friend, go to the very back of the house and whisper, and pay attention because...
   b) If the director calls for you to read, get up, get a script and get on stage. 
   c) If you're on stage with one person you've never met, quickly and quietly introduce yourself before you start.  When you're done reading, quickly and quietly thank the other person, and offer a sincere "that was great".  (They just might be directing the theater's next play! Hey, you never know.)
   d) If you are a smoker, don't sneak out for a quick one.  If you're called while you're out, time will be wasted and attention will be drawn to the fact that you aren't there (i.e. prepared and committed).  Not to mention that you'll stink and others will not enjoy reading with you.  Believe it.
   e) Don't have the "Garlic Surprise" for dinner on audition night.  If you do, keep some mints handy, the kind that can be quickly crunched and swallowed when you get called. 
   f) Lay back on the perfume and cologne.  Unscented deodorant will do just fine.

9. Tricky one here: pay attention to what others do.  You may see/hear someone do something that the director expresses delight with, and might try it to show you can do that too.  On the other side, you don't want to always do what everyone else does, you want to stand out a little bit too. Like I said, tricky one.

I'll close with one last tidbit.  Audition for everything you can (unless you definitely don't want to be in the play - that's just a waste of everyone's time).  It's good practice.  If you aren't right for it, you won't get cast, and that's okay.  When you're right for it, you will be.  And just being seen will get your name and face out there, and you may be right for the next play the theater or director does. 

Break a leg!