Congrats on your new addition. Miniature dachshunds are a joy to have around but can be quite challenging. I have a 7 month old female smooth coat miniature dachshund and I'm still learning new things every day.
Make sure that you always support your pups back, no jumping off high furniture, or stairs. Their backs are very fragile and can become a problem in the future. Also be careful to not allow him or her to become overweight. Any additional weight can cause stress on their back.
My advice would be to be consistent in socializing him or her to all different kinds of people and animals. They can become one person dogs and not do well with strangers, and depending on what type of coat yours is depends on how much this plays a factor.
These dogs are incredibly intelligent, the things I see my pup do and figure out on her own blows my mind. She is a problem solver. With that being said she also is very stubborn and has a mind of her own. Sometimes it's about convincing her that what you want her to do is her idea. Consistency is key. Start young with basic training and manners.
They are a challenge to house train so you will be best off crate training him or her.
Do as much research as you can on the breed and get as much advice. Every time I run across someone who has this breed I take advantage of it and ask everything I am struggling wi
Every dachshund is different and has their own personality so with every bit of information you obtain be sure to recognize your pups own personality.
The challenges I face with this breed are sometimes a lot but I wouldn't change it for anything because she brings so much joy into my life and she just loves unconditionally.
Another note is be careful where you walk. They are what I call shadows and are by your feet all the time so you learn to shuffle so you don't step on the wee thing.