First, you find flowers, then you can make yellow dye, the overworld is the best place to look, try forest or hill biomes.
No, the best place to find diamonds are on level 10-15.
This is not the place to find out about Minecraft. Look at the Minecraft Wiki to find out about the game in general.
The Nether Core
As Minecraft is on online game, the best place to look for tips and strategies on the fan sites or forums catering to Minecraft online. Often the official game forums are the best place to find information and links to other more popular or updated fan sites.
Same place as the computers vanilla Minecraft.
The best place to find the contractors that you need is in the yellow pages of your phone book.
The best way, is to make it. You might be able to find a place that gets full costumes on google. The official minecraft store sells creeper/steve heads too, so thats a start. Be creative!
You can build your house anywhere you want in the world of Minecraft. One of the best places is to build where you first find coal. Also, try to build in a place that's flat.
Underground
About 8~15 blocks above the lowest bedrock you can find. Making a staircase to the bottom of the world, then counting up is recommended.
"The best place to find a Mitsubishi dealer locator is either on the Internet or in the local phone book yellow pages. If a particular model of Mitsubishi is desired,it is always best to contact the dealer before going on site."
Coal is very common. Caves are a good source of coal, but if you are mining, coal is most common at y=48.