Getting a New Puppy

Question
I am considering getting an Australian Shepherd puppy, but I have a dog already and I'm worried he might not like it if we got another dog. His name is Teddy and he's a Dachshund. He loves people, is very calm, loves to play, and is incredibly smart and mischievous. He definitely doesn't fit many breed standards when it comes to his size and personality which is one of the reasons I don't trust most sites about Dachshunds. As I was saying earlier I am thinking about getting a puppy. I was planning on getting one of the calmer puppies from the litter. I was just wondering if there are certain things to watch out for when getting a new puppy. I was also wondering how I should introduce the two. I have heard many different techniques but I wasn't sure about any of them. I just need some advice because even though my parents have had multiple dogs before I never had and I am not sure how to go about adding another dog to our family. One another thing! Should I try to get a female or male puppy. I haven't decided yet on the puppy from the litter yet and there is a girl and a boy I really like. Anyway, thanks for taking the time to read this!

Answer
Hi
Getting the opposite sex is always the best choice.  That is the best insurance for them to get along.  An adult dog usually doesn't like puppies in the beginning so go SLOW until you know whether your dog is the "motherly"/"uncle" type or not.  Getting the calmest is the best as an Aussie is very active and mischievous.  Keeping them separate, the pup in a crate and reassuring the older dog he hasn't been replaced is the first rule.  Feeding separately is a good idea as that can lead to problems if a pup decides, unknowingly, to go to the food dish; after all he has been eating with the litter.
Taking them both out for walks and doing a few new things with both is always good.  Something the original dog hasn't been doing.  He will view the new "outing" with the pup as a plus; make sure he is enjoying what you are doing.
The first introduction could be on neutral territory, sometimes that makes it better.  Take them both out to a park and introduce them there.  If things get friendly, take them back to the house and crate the pup.  Try not to change the doxy's routine too much.  Watch your adult dog for regression in housebreaking.
Your Teddy sounds just like my daughters mini, her name is Bootsie.  She is only 4 pounds.
nancy