You can also drop items for other players to pick up using 'Q'. Only want to smelt half your supply of iron? Pick up half of your stack using right-click. Hold shift to mine or place a single block and pick up half a stack of items using right-click.
You can switch to whatever is in your main hand by using the 'X' key. These are your main and off-hand items, which can be switched between using the 'Z' key. What's the point of those two middle icons on my hotbar? You can hold 'Ctrl' and the arrow keys to have a look at your surroundings. You can hold 'Alt' to see everything you can interact with in your area, and it will also show your hunger at the bottom of the screen. Alternatively, you can also middle-click on items to interact with them. The camp fire, crafting table, any other crafting furniture, and particular items you find on your travels can be activated or used by pressing 'E'. How do I craft using the crafting table or cook?
I just wanted to get some info out there for those having some difficulty with the game. This list will be updated through the weeks as I think of more things to add (as well as images to spruce things up).
Let's get to it, and start with the most basic of questions and work our way up. There are some questions brand new players always seem to have, and some things those more experienced may just not have noticed or used.