Check your battleground for glass
If you are in a bar-type setting and things look like they are going to go hands on, try to pick the place you will go hands on. Look for stools in the way, friends moving in and around you, the location of bottles and the pool sticks. Notice the trophy case behind you and whether it's made of glass.
If you're inside an apartment or house, look at your surroundings and ask yourself, "What is going to hurt me right now?" If it's a glass table or a cabinet with glass or sharp edges, try to remove the subject to a more suitable environment, or have a backup officer move something that may cause you injury. It's all about taking in the whole area of contact and keeping tactical control. You want to limit your chances of being knocked through a glass door or window.
At times we focus on the person we are dealing with and miss what can obviously put us at a disadvantage. Be safe out there.