Wear full blast protection armor
Carry a shield
Keep a fire resistance potion active
Place the bed from maximum safe distance
Stand behind a solid block before clicking the bed
Use a bow, crossbow, or piston setup to trigger it remotely
Dig a one-block-deep trench and stand in it with a block overhead
Place the bed with your cursor aimed at the far edge of the block
Keep extra blocks ready to quickly wall off the blast
Avoid standing near flammable blocks or open lava
Use a totem of undying if available
Keep your health topped off before detonating
Practice the timing in a safe test area first