Oh so you want to make Terraria hey?
1)Copy the game
3)Look at your poor re-creation of a multi-million (check that) software.
Try and do something original... not just an upfront copy. Why did Terraria get the big bucks? Because it was original...
Now, most new ideas (universally, not just in technology,) new IP are bits grabbed from here and there but actually re-designed and genuinely fresh ideas.
Why should a consumer buy your knock off Rolex watch, which doesn't work well, for (take the price down a bit) $40 when he could just save for $90 and get the real deal?
Hm. But anyway, just use the forum to look for randomly generated ground and digging tutorials
from the FAQ, which is pretty easy to find if you were to look and not get completely spoonfed.