A sunflower is one of the friendliest flowers to embroider because it breaks down into a handful of simple shapes: a ring of petals, a fat seed center, a stem, and a couple of leaves. ALK Stitching stitches two of them side by side in this video, and each one uses only four stitches you can pick up in an afternoon. There is no narration, so you learn by watching the floss go in, which makes it easy to follow at your own pace.
The build order does a lot of the work for you. You outline the stems and leaf veins first, fill the leaves with green, then ring the head with golden petals and finish with a packed brown center. Working from the background forward means each new layer sits cleanly on top of the last, and the flower looks finished the moment you add the last French knot. If you are new to filling shapes, read how to do a satin stitch before you start the leaves, since that is the stitch that gives them their solid, glossy look.
Two of these stitches carry over to almost every flower you will ever make. The backstitch is a close cousin of the outline stitch used on the stems, and once sunflowers feel comfortable you can use the same four-stitch approach to embroider a rose. Grab a hoop, a needle, and floss in yellow, brown, and green, and let's make a sunflower.