colDelay
Golem
http://forums.terraria.org/index.php?threads/ebolag-exes-thread-of-buildmentation.22261/Pretty sure a summon would be useful against a Medusa. Try finding a pre-hardmode summoning staff and then go after a Medusa.
Here's a blueprint of a fully automatic efficient pre-Mechanic slime farm. Got me the Slime Staff in about 1-2 hours (~1700 kills). And, yeah, it is worth getting it.
A plain Cactus Sword is enough to make me feel safe. After I have gotten that, I pretty much spend all nights farming for money(yes, on expert mode too).For me It's much harder from the beginning if you are starting from rock bottom. (I kinda cheated and started my character off with by giving him a warding aglet, and a flintlock + ammo.) However I took things slow. Namely the Nightime mobs got a huge buff. I find dirt layer underground safer than nighttime on the surface. Build in the day, mine at night. In normal mode you can pretty much fight zombies at any time after the first night. In expert, I didn't feel safe fighting them until I had 20 defense and a tungsten broadsword.
i'm probably going to wait until I have full gold gear before I go to the crimson.