User blog comment:Terrariamaster320/rage quitting on terraria/@comment-4581788-20120208140928

One other way to save your world and work from destruction: 1: Count down your world list to the world you wanna save. 2: Goto C:\Users\"username\My Games\Terraria\Worlds\ 3: Copy the world#.wld and world#.wld.bak files of the world you want to keep safe, and place them in another folder. 4: Now, you have an untainted backup, should your world be destroyed (update it as changes are made that you support). 5: Don't let people like your supposed friend back in your world in the future. He is just trolling you.

As to your questions of how to develop the skills of some of the youtubers, there is 2 answers, one which may apply to you, and one which can apply to you: Talent - Just being naturally good. Some people are, some aren't. Skill - Practice makes perfect. Not everyone starts at the same level of skill, but many people can get to a higher level with effort and time investment.