Afternoon Tea, a truly British event, was started by an English Duchess as an afternoon gathering for her friends but quickly spread throughout London to be the institution we know today. It's an event that offers occasion for relaxed conversation, gossip, hospitality & friendship.  It can be as simple as a pot of tea with dainty sandwiches & cakes, to three courses that include savory and sweet foods.
    To keep Afternoon Tea fun, change the food, place, tea types and perhaps include a theme. In spring, have your afternoon tea in a room that gets lots of sun and have light foods that go great with spring.  In summer, have it outside on your patio and keep it light and refreshing.    In fall and winter, a fire in that fireplace with some hearty teas and foods go great together.
    So why wait?   Look at your calendar, pick a date, think about a guest list and get started. Invite your guests via e-mail, phone or better yet do a simple hand-written card. Give some thought to the menu as it relates to any theme you may have selected.  A typical afternoon tea includes dainty sandwiches, cakes, pastries, breads, scones and cookies.  An idea this author uses is to ask each person to bring a dish or tea variety to supplement the hosts menu. This creates an excellent variety of foods and desserts.  Prepare as much as possible in the days before the party,  so YOU can be relaxed and enjoy this party. The main thing is NOT to worry if things are not picture perfect ....its a good bet your guests would be happy to help. If you are short of teacups and saucers, ask some friends to bring theirs.
    On the day of the party, choose your teapot and accessories,  tea types, and get your foods ready. Prepare the place you will host the event, be it the yard, living room, sunroom, etc. Be sure you have enough chairs. Gather tea condiments (sugar, cream & lemon slices), standard condiments like butter, jelly, and jam, and any other things that go with your specific menu. Flowers and lace are excellent uplifting decorations.  Soft background music adds to the atmosphere.
    When your guests arrive, show them to the place you have planned. Make sure all of your guests have been introduced to each other and start off some light conversation. It's now time to start heating the water to make tea.   See Tea Brewing Tips. Its now time for YOU to enjoy the conversations with good friends over a nice cup of tea. A closing idea would be to prepare small token Thank-you gifts,  or write Thank-you notes for coming in advance of the party and give to your guests as they depart.

Source: http://www.teaconcepts.com/dTeaParty.asp