Make your list from herbs that are local, safe, and that have uses that you can apply to your life. Once you have your list do a little light research and see if the plants are endangered or rare. If they are, try to find plants that can be used as substitutes so that you don't add to the problems that the plant is facing. Next make a list of common problems that your household faces. Now go to your herb list and compare which ones will cover which problems.
Some plants have multiple uses.
For example, German Chamomile can be used for nerves, stomach problems, a salve for booboos, in tea blends, and as an anti-fungal. This might allow you to cross a few other herbs off of your list and narrow down your studies further. It really is better to know a few herbs thoroughly than dozens of them only slightly. Once you have your list of herbs grow them from seed. Spend an entire year watching them move through their various stages of growth.