German Twisted Cast On
The German Twisted Cast On is similar to the Long Tail Cast On (same hand position, even) but creates a neater, more substantial edge. It's a great multipurpose cast on and is stretchy enough for many different kinds of projects.
I like this tutorial, which starts with a comparison between Long Tail and German Twisted. If you use a slip knot to anchor your first stitch (like I do), just make your slip knot and then follow along.
One thing to keep in mind with the German Twisted Cast On is that how much room you leave between stitches as you cast them on will determine how tight your cast-on edge is once you start knitting. It can be helpful to place your right index finger in front of the last stitch on your needle as you cast on the next one and only snug the new stitch up to the opposite side of that finger when you need to make sure your cast-on has a good amount of give.