Before you enter any avalanche terrain, you must have:
You should also have a cell phone, first aid kit, headlamp and shelter (e.g., rescue tarp), and consider a helmet, map, airbag, etc.
How you wear your gear can affect your survival:
Make sure your probe and shovel can be accessed quickly—they should be stored in a dedicated compartment inside your backpack (and don't store your probes in their little stuff sack). If they're on the outside of your pack, make sure they can't separate from your pack regardless of how hard you are tumbled. It's not uncommon for avalanche victims to become rescuers.
Although helmets have limited effect on rapid deceleration injuries, they undeniably reduce traumatic brain injuries. If you wear a helmet, make sure it is sized correctly, the chin strap is secure, and consider wearing it on the up-track, too.
Leave your earbuds at home. You might like to groove to music in the backcountry, but doing so may prevent you from hearing "Avalanche!" and they'll undeniably discourage ongoing safety discussions with your partners. It is also likely that your media player will interfere with your avalanche transceiver.