I have an aggressive barker, any suggestions!?

Question:
 I have a rott./b.collie mix. she is quite large and sometimes people take her barking offensively, and she doesn't like strangers touching her (esp. men). I have enrolled her in obedience class, but it doesn't start until 1 month from now. I really need some help now though.
Answer:
 Dogs bark for a variety of reasons: out of boredom, warning, lonely, fear, communication, to get attention, it is fun, etc. Some breeds, like many herding breeds, may be more vocal than others. For example, my beloved Shetland Sheepdog is a breed prone to barking. They use vocalizing as part of herding. Shelties can be very vocal dogs! Training from day one when barking will and will not be permitted is very important! Many Shelties are given up each year due to barking. Many dogs PERIOD are given up each year due to barking. However, this need not be. Barking is a problem that can be worked with if you are consistent and diligent. The easiest thing to do is NOT allow barking to get to be a bad habit. As soon as your puppy or dog joins your house, you need to start teaching what will and will not be allowed. Use a command such as NO BARK or ENOUGH and reinforce it with praise as soon as the dog quiets down. Use a firm but not yelling voice and again, yelling can sound like barking and make the situation worse as you are barking as well! Show the dog that you really like it when he is quiet. Just shouting NO can sound like a bark and get your dog even more exited and barky! As soon as the dog stops barking, you need to reinforce the stopping of barking with a treat and praise. No puppy is born knowing commands. You have to teach that each command has an action and if that action is done, good things will follow. Positive motivation is a great training technique! Be careful not to inadvertently praise behaviors you do not want. Cuddling and stroking a barking dog can give the dog the impression you like what it is doing. If your dog is alerting you to something, teach him that when you have checked out a situation and you have told him it is fine, he must stop barking. My dogs learn that I want them to alert me to things on the property or that could pose a threat. As soon as a pack leader has checked it out and given the all clear, the dog does not need to alert me anymore. (I say, "Enough! It's fine" this is their cue that I have given the all clear and alerting me is no longer needed). If your dog is bored or lonely, you need to get active with him. Toys, games, training, interaction all go a long way to help a bored or lonely dog. A tired dog is generally a better behaved dog. Boredom and loneliness can lead to other undesired behaviors as well. Get a variety of toys like Kongs, safe chew toys, Buster Cubes, etc., that will stimulate your dog's mind and get him doing something. Obedience lessons, Agility or other sport as well as just playing fetch will help. Do not leave him outside all day unattended. Dogs who are outside all day especially when no one is home are more prone to becoming nuisance barkers for a variety of reasons listed above as well as a big one: NO ONE IS HOME TO TEACH HIM PROPER BEHAVIOR. If no one shows him what he can and cannot do, the issue will persist. If your dog barks during play, calm the play down. Relax the dog and start again. Keep play under control and integrate training into the play. Some dogs are pathological barkers and intervention with a behaviorist may be needed if training does not work, you cannot find the source of the barking, etc. Sometimes just having a trainer or behaviorists watch your dog can help give you ideas. Now, many people want a fast and easy way out and may resort to various collars that stop barking. IfCollars negatively reinforce the barking through a shock, noise, or spray with a scent dogs do not like. However, you also have to be there to praise the desired effect – the stopping of barking. Some dogs learn to ignore the collars. Unless used properly and part of a training program, these collars can have a high failure rate. The best thing to do to help with barking is not to allow it to become a habit in the first place. 1) Train from day one what will and will not be allowed. Remember, some breeds are more prone to barking, but any dog can be a nuisance barker. 2) Teach a command that lets the dog know you want him to be quiet like NO BARK or ENOUGH. 3) Keep your dog inside when you are not home. Dogs left outside alone all day are more prone to nuisance barking. 4) Obedience training. 5) Adequate exercise, proper attention to him, mental and physical stimulation. A dog that gets what he needs mentally and physically is less apt to be a problem barker. 6) Teach your dog when he can bark and that once you have checked out a situation, he can stop altering you. 7) Try to find the trigger of the bark – like neighborhood kids teasing the dog. 8) Do not inadvertently teach the dog that constant barking is good. 9) Positive training methods to encourage the dog to stay quiet when told 10) Do not let the dog get away with barking for hours before you tell him to stop. The dog may be getting set to stop anyhow and he is also getting attention from you. Stop the bark when it first starts.
Answer:
 Thanks for the great suggestions! I am really working on why she barks; you gave me some ideas! I think that she barks because she thinks she needs to protect me or something. I have noticed that every time she barks either somebody or something is in my yard, somebody is coming towards her or me that is not familiar or something seems out of her order (I hope that makes sense). I forgot to tell you that I had rescued her and don't know her background. Again thank you, your dog expertise is going to good work!! -sswotc