The long tail cast on is an excellent go-to cast on to have at your disposal.
How to knit a long tail cast on
A brief overview
[short version] Set up: Drape the yarn over the right needle with a long tail hanging towards you. Grasp both ends of yarn and tail with the last 3 fingers of your left hand and put your left thumb and forefinger between the tail and yarn while holding the yarn in your palm. Open your thumb and forefinger and move your left hand so the thumb and forefinger are pointing upward. At the same time, bring the needle and your right hand backward so the needle is pointing upward.
A more elaborated description
Set up: Hold the yarn in your right hand so that a long tail hangs towards you. Put the tips of your left thumb and forefinger together to make an ellipse and drape the yarn over the first knuckles. Loosely grasp these 2 strands of yarn (the tail and the yarn coming from the ball ) by closing the other three fingers of your left hand into your palm. Now, open your left thumb and forefinger to make a slingshot.
Step 1: While holding the yarn on the needle, *turn your right wrist so the needle is positioned to go from the pad of the thumb, up and underneath the yarn at the base of the thumb and into the closed loop now created. Bring the needle up and over the first yarn on the forefinger, scooping that yarn and the needle back into the loop on the thumb going in the opposite direction you came out, moving toward the pad. Once the needle has cleared the loop and you can see a new loop on the needle, slide your left thumb from the loop and use your left thumb to pull the tail and gently tighten loop on needle. Don’t pull these cast on loops too tight.
Step 2: Hold the needle with the loops on it parallel to the floor with 2 strands of yarn hanging from it. Put your left thumb and forefinger together again and go between the two stands. Grasp the 2 strands again with the other three fingers, then turn both hands so palms are facing each other while opening the left thumb and forefinger. You can now move your hands so the needle is in the loaded slingshot position.
