So, I went to a Christmas party last month (obviously) and the centerpiece on the dessert table was gorgeous. It was just calla lilies and some red berries in a tall vase--so easy, but so pretty! Well, I was currently vase-less, so I asked for a tall vase for Christmas.
No tall vases, but I did get a Jo-Ann's gift card (hurray!) for Christmas, so I picked one out for myself. :)
I had some silk flowers left over from my wedding--that's actually Mr. MadeIt's boutonniere sitting on the right of the vase--so all I had to buy was the vase and the little glass marbles to keep the vase stable.
Well, I don't know much about Floral Design, but my sister majored in just that department, so here she is to give you some tips!
Well, this centerpiece is for a table where people will sit. With that placement, there are two options: tall and thin, like what Jill did, or short. The point is to make sure it doesn't block people's view of each other--otherwise, someone will put it on the floor.
When using a tall, thin vase, you can use long stemmed flowers like Jill, but you don't actually have to. If you only have shorter flowers, you can do an arrangement that is completely inside the vase. (I actually think live flowers submerged or floating in a tall vase are beautiful.)
Just some basic things to consider:
Scale: Keep the centerpiece components in proportion to each other and to their surroundings. A small arrangement on a big table will be underwhelming. One large arrangement, or several small ones will look better.
Color: The basic color schemes are monochromatic, analogous (using colors that are next to each other on the color wheel---red, orange and yellow, blue and purple, etc.), and complementary (colors that are opposite each other on the color wheel---red and green, blue and orange, yellow and purple). Using complementary colors will give you high color contrast, and using analogous colors will give a softer contrast.
For the purpose of flower arrangements, green is not a color unless you're using green flowers. All plants have green, so it's ignored. So, you don't have to worry about making the foliage fit your color scheme.
Feel/Mood: Consider the feeling you want to create or complement. Big, bold flowers for a little girl's fairy princess birthday party might not be the best choice. Light airy flower and leaves might fit better. Also, do you want the arrangement to be dramatic or subtle/soft? A show-stopper or an accent?
Balance: An arrangement needs to look stable. If it has a big bloom stretching way over past the edge of the vase, unless it has something to visually balance it, it will make people uncomfortable because it will look like it's about to fall over. Large things have more visual weight then small things (surprise!), and dark things have more visual weight than light colored things. Sometimes you can even provide balance with a knickknack next to the arrangement.
Symmetry: You probably already know the two kinds of symmetry--symmetrical and asymmetrical. Symmetrical things are probably easier for beginners. For asymmetrical arrangements, just keep in mind that things need visual balance.
Here's a rule that is helpful for any artistic endeaver: step back once in a while. It will help you see what's working and what isn't.
Finally, have fun and experiment! Remember, unlike painting, drawing, sculpture or other art forms, your materials are beautiful to begin with. Your job is to show them off.