Selection of Yarn and hook
Make sure you choose the yarns according to the colors you wish to be see in your scarf. If you intend to use a regular five ounce yarn, then use an ‘I’ hook otherwise use ‘K’ hook.
Another row of single crochet
As an example, if you have to crochet 21 chains for the width of your scarf, then go for one more row of 20 chains in a single crochet. In order to make sure you have not missed any, keep counting your chains.
A safety measure
In case you run short of the yarn, always have a good stopping point as you crochet. This will not only help you if you start a new spool, but also will be useful for a multi-striped scarf. It is advised to do this using a plastic needle and at the very end, when the desired length of your scarf is achieved.