Coming from a large dog owner, and that breed is a guard and protect breed, it is very important to understand leash control and to obedience train your dogs.
How-ever it is just as important with small or toy breed dogs. There is in the court of public opinion, when you are out in public with your dog, to have your dog under control.
Sometimes the paramount reason for toy dog owners is to be able to re-act fast and protectively towards your dog, if he is threatened by other dogs, or some idiot member of the public.
So how to hold the leash? The way I was taught many moons ago, is to link the handle over my thumb and thread the leash through my other fingers. Also with small breeds you could place the whole handle over your wrist and thread some of the lead through to at least one other finger and then your palm.
When approaching strangers and or strange dogs, be ready to short lead your dog. There are a couple of ways to do this. Shorten up on the threading of the lead through your fingers, and or, place your second hand halfway down the lead. And of course short lead your dog!
The second suggestion is more applicable to large breed dogs, if you need to, you can really use your body weight and leverage to "stop" your dogs charge, or at the minimum to turn their head. But with large breeds, unless you have obedience trained them, it would not be enough, especially with a real threat your dog perceives, and or, you only weigh as much as your dog!
A very rough rule of thumb, for every 1lb of dog weight = 3-4 lbs of human weight.
You only need to be pulled off your feet onto your face once, to get this lesson really really fast.
Quite frankly if I see a large dog owner approaching me, with no leash control on their dog, not only do I short lead what-ever dog I have with me, but if possible I cross the street, if not possible I take as wide a berth around them as I can.
And BTW I also do that with any size of dog on a Flexi lead. I do would like to see those leads banned from pet stores, and you could only order them from working dog sites.