If you have a tendancy to move away quickly to look at what you have taken then place your camera in continous mode. Take 2 or 3 shots in a burst, this will make you stand still longer.
As you press the shutter release breathe out slow. Don't move until you have emptied your lungs!
You don't want to take a tripod out on a walkabout. So try to make yourself as stable as possible. Wide stance, left elbow (if your right handed) tucked in to your body. You can also use props around you, walls, seats, lamp posts, in fact anything that is solid. Lean your hands, shoulders or camera on them for stability.
One other thing, watch others. If you see someone else who looks like they know what they are doing watch the technique they use.