I have a love for fabric. The colors and textures appeal to me on many levels. I can spend hours at the fabric store looking at different patterns and feeling the luxurious fibers. While there are many, many things to know about fabric, when first starting out, you need to know a few basics.
Most fabrics you work with will either be woven or knit together. A woven fabric seems like a basic grid of threads woven together in perpendicular patterns. This fabric here is a loosely woven fabric; you can even see the weave easily with the naked eye.
Knit fabrics are stretchier, and people often find working with knit considerably more tricky. The picture above shows the pattern in which knits are woven. It's the loopy weave that lets the fabric stretch in multiple directions. You will want to know the difference between a knit and a woven fabric when choosing fabric for project as they behave differently.
Most projects and patterns will reference the "right side" and the "wrong side" of the fabric. Many fabrics will have one side of the fabric that has much richer color, and is the side meant to show in a project. The other side I often think of as the back of the fabric: the side that is meant to be hidden.
The final piece of basic information you need (in my opinion) about fabrics is what is meant when talking about grain or bias. The grain is the direction that the fabric is woven. Bias is a 45 degree angle from the grain. Fabric holds its shape when sewn based on the grain, and stretches when sewn according to the bias.
I am lucky enough to have a mother that is a walking encyclopedia of fabric information, who has taught me all about fabrics, but for those of you who don't have a mother like mine, I recommend purchasing Fabrics A to Z by Dana Willard (author of Made). She is one of my all-time favorite bloggers, and wrote an incredible reference book that is small enough to fit in your purse, so you can take it with you to the fabric store.