Go make traps and purify the corruption. Keep seeds handy, and try to control the hallow enough so it will not spread. Smash some demon altars, checking for corruption. If there is any that you see, purify it. Go mine enough cobalt for a sword, a full set of armor, and 80 extra. Do the same with mythrill, and then with adamantite. Once you have a full set of adamanite armor and a sword focus on getting greater healing potions. If you like ranged damage, try to get a repeater, megashark, or shotgun. Try to get cursed bullets or high tier arrows for ammo. If you prefer magic damage, get a crystal storm or golden shower. For people who like flails, go for Dao of Pow. I personally think you should try to get everything. Use the flail is for when he is in a straight line, the crystal storm for close up attacking, and the shotgun for extra damage.