I have a 14 months small breed dog and I have the feeling that I can't train her at all! Her training was very difficult from the beginning. I tried a lot of different training techniques but only work for short-term. I think that the major problem is that she feels that is the Alpha dog. Because she is very cute me and my wife over-spoiled her and now if she doesn't get what she wants she barks, jumps, try to bite (not hard, just to get attention). I tried the techniques of how to became the Alpha dog but they don't work for me especially because we are very busy now and we don't spend a lot of time with her. Is there any way to make her a good behaved dog or is it to late now?
So you admit that you and your wife spoiled your 14 mos old puppy.
The most important thing in training is to be "consistent and patient".
You said you tried all kinds of training techniques and maybe it might have confused your puppy and it doesn't sound you have been consistent.
For example, if you want to control her, instead of being controlled (or manipulated) by her, don't give in to her. She barks, jumps and nips to get your attention. She has leaned that it works from her experience. To break this cycle, you and your wife (and any other people who deal with her) should ignore her completely when she is acting like that. She will soon figure out it's not working anymore. In the mean time, give her a treat and a lot of praise when she behaves the way you want her to.
I know you are very busy but can you give her 15 min training session twice a day, but EVERY DAY? Make it as a routine.
Make her sit/down and wait. You turn around and walk a few steps and call her. When she comes, treat and praise. You will repeat this 5 times.
Make her sit/down and stay. You turn around and walk away and walk back to her. If she is still there, treat and praise. 5 times of this.
You can add "distance and duration" little by little. You will be able to leave your dog at one spot and go to another room and call her eventually.
A little daily practice goes a long way. Good luck. Remember "Don't give in" when she barks, jumps, and nips.