Things I like to have on hand when beginning a needlework or creative embroidery project:
Woven fabric is best to start with - linen or cotton in a mid-weight works best
Lots of thread, yarn so you have options
Scissors (shears and snips or embroidery scissors)
Needles - various sizes and lengths that work with the yarns and fabric you have on hand
Embroidery hoops - they create tension on the fabric and it makes it easier to sew through
Beeswax to help keep threads from being unruly
Marking tools to transfer designs to your fabric
Wash-away stabilizer (also for design transfer)
Thimble
There are two books I really love when it comes to needlework:
The Reader’s Digest Complete Guide to Needlework
and
The Geometry of Hand-Sewing by Natalie Chanin
They both have detailed descriptions for supplies and terms used in stitching and there are many illustrations and photos detailing technique. I find them extremely useful and return to them often.
It helps to think of stitching techniques as you would think about drawing:
The language of drawing can be simplified in terms of line and shape. The language of stitching can be simplified into outlines and filler stitches. There are many variations but all stitches are built off of very basic concepts. This is partly why I think creating complex looking motifs, designs or patterns is truly accessible once you understand the basic building blocks.