Zinnia is pretty easy and a lot of fun. Plus, zins love to germinate, so they're fun to grow. My only bug a bear here is that I tend to start them too early and they get nailed by cold temps. But I manage to get some each year.

At the inside end of each petal is a seed that resembles an arrowhead. It's really obvious in things like those huge garden zins and smaller and slenderer in zins like red spider. When the flower is dry, those arrow heads will shake out from the rest of the chaff. Sometimes they still have a dried petal attached. I grow them outdoors, so chaff doesn't bother me a bit.

I would take a dried flower, crumble it and sort out what looks like an arrowhead. You can see where they specifically grow on each plant. Once you figure out how to harvest zins, you are all set!

The petal end seeds is also the same principal in many flowers including heliopsis.

After I dry my seeds, I put them in zippered mini baggies that I label with type and sowing instructions. I then put them in metal cake tins and store them in the lower part of the frig. Many plants have to go thru a cold spell first before they will germinate. The frig seems to keep them in suspended animation and they are always ready to go!