Use a protected battery or fuse for one thing.
Not exactly...
Use unprotected IMR safe chemistry batteries, or IMR hybrids. Popular choices are Sony US18650VTC4(or 5) for way sub ohm, or Panasonic NCR18650PF for resistance down to .6Ω. Efest also has new purple high-amp batteries that are becoming popular. I just bought some Efest 18500 purple 15 amp batteries. They work very well.
Also, use a decent charger. A very good budget model is the Nitecore i2 or i4.
Also, use an ohm's law calculator to check what resistance your battery can handle (amps wise). A fresh battery is considered to be 4.2 volts. Always do your calculations based on a freshly charged battery, just to be safe. Allow yourself some wiggle room too, because even though your battery might support a .2Ω coil, you want to think of safety above all.
Check your battery sleeves often to make sure there aren't any scratches, or missing pieces, which can touch the side of the mech and complete the circuit even though the button isn't being pushed.