Skeletron becomes easier when the arena gives you room to move and your loadout is familiar enough that you can focus on the fight itself.
Create clear movement lanes
Remove terrain that interrupts movement and give yourself enough space to react consistently.
Use a weapon style you already understand
A familiar attack rhythm is more useful than switching to an unfamiliar option just before the fight.
Prepare recovery before the attempt
Make healing and other consumables easy to access.
Use failed attempts as information
Identify whether movement, damage uptime or survivability is the main problem before changing the setup.