Start with a fresh account or an account with very low combat experience
Keep Constitution/Hitpoints at level 1 by never gaining HP experience
Train Slayer only through methods that do not award HP experience
Use lamps, quest rewards, or other non-combat Slayer XP sources when available
Avoid any combat that deals damage and grants HP experience
Do not use weapons, spells, or abilities that can hit enemies
Use safe, non-damaging methods for Slayer tasks if the game version allows them
Complete Slayer-related quests or activities that grant Slayer XP without combat
Check every XP source before using it to ensure it does not award HP XP
Stop immediately if any action gives HP experience
Keep track of Slayer XP and HP XP after every training session
Continue until Slayer reaches level 30 while HP remains at 1