Wood can be used as a fuel for a furnace.
It doesn't last as long as coal, but it's easier to get, too.
I've also noticed some people use wood logs are a fuel.
Don't; use wood planks, it's literally 4x as efficient.
Also don't use wood tools for long.
Use a wood pickaxe to mine some cobblestone, then make stone tools out of that.
From there, mine iron ore (not sure what it looks like with default), and smelt it in a furnace to get iron ingots. Use those to make tools. Wood will not successfully mine coal or iron (is that right?). Stone will, but it wont when you try to mine lapis luzuli, the navy blue ones (?); redstone, the red ones (?), gold, or diamond. I don't suggest golden tools at all. Save all your gold for redstone contraptions. Even in real life gold is a very soft metal. When you get diamonds, treat it just like you would iron.