It can take many years to accumulate enough knowledge to identify every type of fabric that you can come across, and once you obtain that knowledge, your memory banks may be so full that you experience lapses. There are is a simple solution and you should start this project when you start buying fabric.
Create your own fabric identification notebook. Every time you buy a piece of fabric, make a note of the information found on the end of the bolt. Most cell phones can take pictures and this is a great way to store the information from the fabric bolt, but a picture will not replace the scarp of fabric and can not replicate actually feeling a piece of fabric. If you are a real scrap-oholic, consider making a visit to the fabric store just to purchase minimum amounts of fabric for your identification notebook. Remnants bins are an economical source for small pieces of fabric.
Once you are home, grab a notebook and use a two inch or larger square of the fabric to make your own notebook page. On this page, you can include, the name of the fabric, the fiber content, and any other information obtained from the end of the bolt, including what you made (or plan on making) with the fabric. You may even want to add a picture of the item once it is done.
Another method to identify fabric contents is a fabric burn test. This will tell you what type of fibers make up the fabric in question. This helps match laundering and pressing needs but does not give you the name of the fabric.