How do I save seeds from a plant I'd like to be able to plant next?

When the plant starts getting brown and dried up then cut the flowers and put them in a brown paper bag. Be warned that some seeds are engineered not to grow new plants.

Put them in an envelope, label and put in fridge until next spring. Plant in peat moss pods, in an old muffin tin, water well, put in toothpick to hold up plastic wrap cover, set in sunny window a month before your normal last frost in NH. Remove plastic wrap when sprouts start and plant when you have two sets of leaves after pinching down the first set of leaves. Good luck.

Collect them and put in brown paper bag till spring.

Dry the seeds on a counter for a few days. Put each type in a separate envelope. Label the envelope with the name of the seeds, the year harvested, where you planted the seeds, and how well they did. Save the envelopes for the next year. 😇💖

Make sure the seeds are completely dry then put them in a plastic container with lid. Label what they are and put them in your freezer. They will keep for years as long as your freezer stays in good shape and runs good.SSL

Old medication bottles are great for saving lots of things. I have put jewelry in some to keep items clean.

save them in a paper bag, this keeps them from getting moist and getting moldy