Gather your materials:
•    Teas and spices
•    Blending bowls, spoons, mortar and pestle
•    Brewing equipment (teapots, paper tea bags, tea strainers, teacups)
•    Winter fruits, nuts, and chocolate for snacking (or have your guests bring their favorites!)
•    Packing materials (bags, jars, tags, twine)
Decide which base teas you’d like to provide for your guests’ blending pleasure.

Black tea flavor pairings
Assam (a black tea from India) lends itself well to chai and other spicy, robust blends.

Green tea flavor pairings
A toasty Chinese green tea like Dragonwell is delicious with a few jasmine green tea leaves or cacao nibs tossed in, while Japanese sencha (a grassier, greener green tea) loves a dash of matcha powder and mint or citrus peel.

Rooibos flavor pairings
Red tea, or Rooibos, is not a true tea in that it doesn’t come from the tea plant, camellia sinensis. It is caffeine free (perfect for sipping in the bathtub before bed!) and has a rich and honeyed flavor. It’s just perfect with exotic chai spices, or with peppermint and cacao for a soothing dessert tea.
Here is a little chart with a few flavor-pairing suggestions to get you started:
Assam
Green tea
Rooibos
ceylon cinnamonwinter citrus zest: meyer lemon, blood orange, tangerinecacao nibs
cardamomfennel seedssaffron
ginger, dried or candiedmintshredded coconut
peppercorns: black, pink, long peppercorns or grains of paradiselicoricegolden raisins
rose petalslemongrassrose petals
vanilla beanscacao nibsginger
dried berriescandied gingerpeppermint
cacao nibsmatcha
Find a spot to lay all your ingredients out, and if you have small ramekins or finger bowls to fill with your spices, so much the better. All the teas and spices set out in pretty little dishes on the table should look like a scene from an exotic banquet. Have a full tea kettle on hand, as well as tasting teacups for your guests.
You can group suggested ingredients together with their respective teas to make blending simpler, though a few ingredients will be perfectly happy to cross those boundaries. You could also stick with one base tea for everyone to simplify the whole affair and then marvel at the variety of different blends that result.
Set out bowls and spoons for guests to blend their tea, and put on the kettle for test runs. A mortar and pestle can be helpful for crushing spices to make chai. I like to have some unbleached paper tea bags on hand to fill with teas as the blending progresses, to see if the flavor is just right. A good rule of thumb is to start with just a little of what you’d like to add and let your nose guide you as you go along. Then do a few taste tests to fine tune your creation and appreciate the magical way that hot water releases the flavors. Many tea blends also benefit from a period of marrying, or allowing the flavors to come together in the finished blend.
Drink plenty of tea as you go along! Be sure to observe the correct brewing temperatures for each base tea, in order to bring out the best possible side of your blends. You can always experiment with time, temperature and amount of tea, and do make sure to write brewing instructions on your gifts tags when you package your teas up.
Brewing Times and Temperatures:
•    Black tea is best brewed with boiling water (212°F) for 4-5 minutes, while black tea chai blends are best simmered in a 50/50 mix of water and your favorite milk for about 5 minutes.
•    Green teas are most often brewed at about 180°F for 3-4 minutes.
•    Red tea is best brewed at 195°F, or just under a boil for 5-7 minutes.
Make packaging. I love compostable brown paper bags for my teas, but glass jars are beautiful, (and reusable) too! Have twine, paper, tape and gift tags on hand to finish off your packages beautifully.