Change the oil and filter. Fill the tank with fresh fuel and mix in the proper amount of Sta-Bil or Seafoam. Run it for a little while to get the mixture into the engine and then kill it. Remove the battery. If you can, store the bike lifted so that the tires aren't touching the ground. Cover it if you want and walk away.
When you return, reinstall the battery (freshly charged), air up the tires and fire it up.