Hello i'm here to tell you an easy way to find resources such as coal,diamond,iron,gold,redstone,lapiz lazuli, and others.
1.Dig down until you reach layer 12 (press f3 and look at the number next to y. that should say 12.
2.Stand on layer 12 and dig 4 blocks high. You should be digging out layer 13,14,15,and 16.(these resources are found in abundance here,You will be standing on 12 and 17 willl be the layer above your head)
3.Dig back all the blocks that 1 iron pickaxe or 2-3 stone pickaxes can destroy.
4. When done go back to main area skip 2 blocks and start another strip.
This way of mining helps me greatly.In 1 week of playin on my new map i got 34 diamond,7 64s of coal,3 64s of iron, 13 64s of redstone, 4 64s of lapiz lazuli, and 31 gold.