How to defeat the Eye of Cthulhu

How do I defeat the Eye of Cthulhu? I got him to half health with just a gun and a broadsword, but it became daytime.

Solution 1:

Prepare the terrain :

• Put a campfire (liferegen)
• Put a sunflower (movespeed)
• Build an area made of rows of wood platforms

The fight

• Summon him @ 7:30pm
• Use piercing attack weapons
• Use a fast swinging weapon if swarmed
• Use the best armor you can afford
• Use potions (life, ironskin, thorns)

You should also read this guide.

Solution 2:

One of the easiest ways of killing bosses is just getting better gear. If you are having a hard time defeating a boss, maybe you should start mining for better materials. The deeper you go, the better materials you find. It requires a lot of patience, and in some ways, luck.

On the actual fight itself, I would recommend using ranged weapons rather than melee, in order to avoid getting hit. Also avoid fighting him near your base/town, as he can kill npc's (I made the town underground to avoid any unnecessary fatalities.) Gear that increase your jumping, flying or movement speed should help in the fight as well.

Source: my experience with the PC version of the game.