The Charging Jack-Chi

We have another question to answer!  The set up for the question is a bit lengthy, but I'm sharing it all with you so you have all the information I have.

I've been having issues with my dog when we go on walks for a long time now and I'm hoping to get some advice. She's a 7 year old chihuahua/jack?/mystery dog mix. She's spayed, and weighs 11 pounds. At home she's always been sweet, she's good for the vet, does well with familiar dogs, and will eagerly make friends with new dogs as long as they come over to our place first. When she was a puppy she was terrified to go on walks, she'd freeze and I'd have to coax her along. She'd always shake and want me to carry her when we'd go to the dog park. Right around when she hit a year she started going berserk whenever she'd see a strange dog during our walks. When my husband takes her, or she's with one of my friends when we're out of town she does better...but with me she goes crazy.
Unfortunately we live in a busy part of a city that has a high population of dog owners, which has turned into her getting pad trained and not walked as often as she should. Recently one of my friends that lives in the same building has been taking her out. For awhile it sounded like she was doing OK, but it turns out she was flipping out on other dogs with her too, and getting picked up. Now she tries to get my friend to pick her up about half of the time when she sees another dog, and if I'm there...she'll stay in full on attack mode until the other dog is out of sight. The last three times my friend took her out, from what I was told, she's started jumping up at strangers and play nipping at their clothes. She's really bouncy, and when we play she'll jump and play nip. But, I'm worried that something might happen so shes no longer going with the friend. I suspect that the issue is her being protective of me (and now my friend), and not getting enough exercise because of the aggressive behavior. What should I do? 

 This is a great question, and it's a common problem, particularly with small dogs, as they tend to show a bit of a Napoleon complex.  In addition, it seems like she may show signs of under-socialization.  So, what are some things you can do?

1) Stop picking her up.
It's very common for the owner of a small dog to try to calm their dog by picking her up and soothing her.  The problem is, this doesn't actually calm the dog.  Rather it teaches her that acting in such a manner will get her hugs and snuggles (praise, if you will).  It will actually amp up her behavior as she searches for more ways to get your attention.

2) Teach her a command.
I'd start with teaching her a good heel command.  Really, any command could work, but the heel command is probably your best bet. 

3) Tell her what you want her to do, NOT what you don't want her to do.
Most people make the mistake of yelling at or trying to shush their dogs when they start barking.  The problem with this is that 1) your dog has no idea what you're telling her to do, and 2) even if she does understand "no" she won't understand why.  So, it's better to teach your dog a command (like the heel mentioned above) and then use that command when approaching stressful situations.  By rewarding your dog when she does the command you've taught her your teaching her that following you will earn her good things.

4)  Slowly introduce her to other dogs / distractions.
Don't just throw her into a long walk with huge distractions, and don't expect her to be perfect right off the bat with another wild and crazy dog.  Introduce, under control, to a calm, obedient dog.  Practice that a few times, then step up to a slightly less-trained dog.  Next, have an untrained, calm dog.  Keep stepping it up until you reach that crazy, hyper dog test.  Through each step, expect her to follow the command(s) you've taught her and reward her for doing so.

5) Consult a Trainer
Whether it seems like it a lot, the steps I just set forth can be quite overwhelming.  You may find yourself asking things like, "Am I doing this right?"  "Is this command good enough?" "Are we introducing her to the right kinds of dogs?"  If in doubt, set up a meeting with a local trainer.  Many offer free consultations or at least cheap consultations.  A great many also offer walking sessions where you can learn to walk with other dogs (a great source for when you are well into step 4).  Don't be afraid to seek the advice of a professional.  That's what we're here for!

I hope this helps to answer your question.  I do have one last tip, though.  Don't concern yourself over what others are thinking.  The number one worry I see in people who have barking / aggressive / excited dogs is what others must think of them.  The only thing you should be worried about is your dog.  By worrying about anything else you are doing your dog and yourself a HUGE disservice.  Good luck!