You may notice I've added a simple chain crochet trim --I'll show you how I did that later too. The first thing you need to know is your needle size and yarn weight. My advice---start with large needles (8.5 mm) and bulky or super bulky yarn. It's so much easier to see what you are doing and follow the directions in photos and books. This hat is made with super bulky yarn using 6mm needles.
So let's start with casting on...this is the method I prefer. I think it's called the double cast-on.
Start with a slip knot
You'll want to make the not about 4 feet or so into the length of the yarn. You'll be using the "tail" as you cast on. If it's too short...guess what you have to do??? Yep..start over. So take my advice and leave extra :) Next you put your needle into the slipknot. I'm right handed so if you're not you'll have to flip the instructions. I'm also using the 8.5 mm needles for these photos so you can see better.