If you are confident in identifying herbs, just cut and dry them now before frost, by laying them out indoors on screens, paper, or in shallow pans. It's not really ideal, they would be more potent if cut earlier in the summer. If you want to find out what plants can be used for tea, PFAF can tell you, you can search their database by medicinal usage.

Here is a link that might be useful: PFAF

You can also cut them and hang them upside down to dry (I bundle the cut ends with a rubber band, run a string through the rubber band and them hang them from a nail). There are many common plants, flowers, and culinary herbs that can be used as an herbal tea... some I can think of... mint, lavender, echinacea, cure-all (common weed in my area - northern VA), lemon balm, bee balm, raspberry leaf, strawberry leaf, etc. If you are interested in using wild plants to make tea you should definitely get a good edible wild plant identifying book for your area but keep in mind that just because they say it is edible does not mean it is necessarily delicious. ;)

Good luck, eating wild food is lots of fun!

pretty much all parts of dandelion can be used for teas, but the most common parts would be the leaves and roots. Also, new green growth from dewberry leaves are used in teas.

The most versatile and easy system for measurements is the simplers method, because it is based on ratios, measurements are referred to as "parts", for instance 3 parts dandelion, 1 part nettle, 2 parts raspberry, is a very common 3:1:2 synergy. This simple way of measurement lets you make your formulation in any volume you wish, whether ounces, tablespoons, cups, liters, grams etc.

Herbal tea making is just as much of an art as it is a science. Color, taste, aroma all will signal you when the brew is "just right".
Ratio : Pour two cups boiling water over one ounce dried herb, (1 to 2 tablespoons), or 1 cupped handful of the fresh herb.
Brewing time : 10 to 20 minutes. Depends on the material. Generally, leaves and flowers will take less time than seeds, roots, or barks.
Average Dose. The average dosage is usually 3 to 4 cups in a day. Bitter medicines need only be taken in small doses, usually 1/2 cup at a time.
Variations : Spices like ginger, cinnamon, cardamom, cloves, and allspice add heat and energy to the infusion. Almond and vanilla extracts, raw honey, fresh lemon, or a pinch of stevia add flavor and zest.
Tools : You don't need anything fancy, the most important tea tool is a non-aluminum pot with a tight fitting lid. Add a strainer and a tea cup and you are good to go.