I used the clicker training methods and used the word "YES!" as a marker instead of clicker. Sometimes I use the clicker, but I often forget to have it with me when I want to use it. So my dog works with "yes" as well. I say it very positively and enthusiastically, like in all capital red letters, underlined, bold, and lots of exclamation marks. I don't have to say it loudly. In fact, as I am in public often with my dog, she responds to most commands if I whisper. And a whispered "yes" works well as a marker and if very difficult for others to hear....certainly it isn't as loud as their conversations on their cell phones. I also use a hand signal to indicate praise to my dog. I make a circle with the end of my thumb touching my forefinger. I hold my hand in front of me and give it a quick stacotto movement foreward....it's a hand gesture often used to indicate OK or Right On. In the beginning I paired it with food treats, verbal praise and touching. Now I can use it all by itself from several feet away if needed to let my dog know she is doing well. I often hear her tail thumping in response, so I know she understands. These might work if you are training in a place where noise must be kept to a minimum. Jo