Tutorials/Materials tactics

Some materials can be 'farmed' or made in great quantities in order to allow easy access to craftable objects.

Flint
You can easily gain flint in huge quantities by collecting gravel. Collect as much gravel as you want to obtain via flint and proceed to a safe, well-lit location (as this is a good thing to get done during the night) and place the gravel in a sufficiently large block (2 or 3 high is adequate). With a shovel equipped, dig through all of the placed gravel picking up any gravel/flint that drops. Rinse and repeat until you have used up all of your gravel. This technique can be done in proximity to a Mob Spawner trap, allowing their 'loot' to build up while you dig. Gravel blocks drop flint about 8.5% of the time.

Another technique is to either outside, or inside if you have a place big enough, look straight down and keep placing the gravel right beneath you. Once you place all of the gravel, simply dig straight down. Using this technique will cause less mistakes and be quicker since they are in a perfectly straight line. However it may be a challenge to find a space big enough to do indoors or be dangerous to do it outside at night.

Another thing you can do is make a vertical shaft. This technique is almost like the above one except that this one you can easily get to the top and bottom and can therefore add gravel to it as you collect it and mine it at time (a good idea is to drop off gravel during the day and mine what you have collected at night). It should look something like this:

This can be as tall as you want it and gives the added bonus of getting some stone and possible ores as you clear out an area to make it.

Obsidian
When water touches a lava spring block, it will turn into obsidian. Miners use troughs to place multiple lava springs on and let the water run over them. This is explained in more detail in Obsidian.

Creating nether portals and mining them from the other side produces an infinite amount of obsidian.

Cobblestone
This type of farming is almost the opposite of obsidian farming. Instead of having water touch lava, you want the lava to touch water. This makes cobblestone. This is deeply explained in Tutorials/Cobblestone_Farming Alternatively, stone can be produced by having flowing lava land on top of flowing water. Keep in mind that stone can not be obtained from a block without a silk touch enchantment

Wool
Wool farming is very simple, and provided you have the iron to craft a couple of shears (which don't take much iron anyway), can be used to quickly provide large quantities of wool for trading, crafting, or building.

Using shears on sheep usually provides about 3 wool. Depending on how much wool you want/need, it is simple to calculate how many sheep you should have in your farm. Collection is also simple; just walk up to each sheep in turn and shear, then move on to the next one. To make it even faster, keep holding down the left mouse button to automatically shear when you look at the sheep.

This strategy can also be used to gather any color of wool simply by dying the sheep the desired color.