A LT, or long-tail cast on, is a method of casting on stitches in knitting. It is one of the most popular methods, as it is easy to do and produces a neat edge.
To do a LT cast on, you will need to measure out a length of yarn that is twice the width of your desired finished project. For example, if you are casting on for a scarf that is 10 inches wide, you will need 20 inches of yarn.
Once you have your length of yarn, make a slip knot at one end and hold it on your left needle. Then, take the tail end of the yarn (the other end not attached to the ball) and wrap it around your index finger once. Next, insert your right needle under both loops on your index finger and knitwise into the loop closest to your hand (the front loop). Now pull this stitch off your finger and onto your right needle. You have now completed one stitch!
Continue wrapping the yarn around your index finger and knitting into the front loop until you have reached the desired number of stitches. When you are finished casting on, cut the yarn leaving a long tail (at least 6 inches) and continue with your pattern instructions!