First and foremost it will be a great way to spend some quality time with your son or daughter. (Yes boys can work with yarn too!)
The charities have a lot of information on their websites, below is some general advice to help you get those needles clicking.
Fastenings: Plain flat half-inch buttons are best to use for fastening. Avoid nylon and metal fastenings, as they get very hot under the incubator heaters. Do not use Velcro as a fastening, it is very scratchy on the hook side and also damages knitted garments when they are laundered. Ease of dressing is vital for preemies and as a general rule it is best not to use ribbon as a fastening as ribbon can often be fussy to tie on a garment so small.
Bliss asks that to reduce their costs volunteer knitters help by sending items direct to their local unit, and not to Bliss. To find the address of your local unit, and to check which items they have requested to receive, please contact Bliss via their website.
Many specialist knitting bags are also designed to specifically cater to knitters, with inner linings that are tough enough to resist damage from knitting needles or scissors being kept inside. Popular brands of knitting bags include methane, Namaste and Bergere de France, but there is a huge range of stylish and practical designs on the market from many different manufacturers.