I'm a grad student. My number one design rule: "Try to find a few unique pieces that keep your apartment from looking like an Ikea showroom."

When planning a garden bed:

some spiky, some roundy, some floofy.

Never paint all four sides of a room the same color.

Jezbella...that is a wonderful tip and easy to remember. Thanks!

I like that Jezebella!!

I say go with your gut and combine what you love and you can't go wrong.

William Morris said it. “Have nothing in your houses that you do not know to be useful, or believe to be beautiful.”

Keep it simple. Clutter is evil!

Not everything has to match! Mix it up and you won't be sorry. And if someone copies your style, take it as a compliment.

Get stuff that makes you happy when you look at it.

Magnaverde Rule No. 1:
Don't confuse decorating with shopping.

Surround yourself with things you love... belongings/stuff/items you will never get sick of looking at.
If you are drawn to something or spy a piece you adore, you WILL find a home for it within your abode, your home sweet home. I have been told my home is like a museum... so many places to look and interesting things to view. I like that. All that is mine is an extension of who I am. I simply love my home -- it is a reflection of me!!

Don't feel you have to be completely trapped in a single style. You may see something you absolutely love but don't feel it fits the current style of your home. That one piece might bring new energy to an entire room or even set you free from the confines of a particular style you may not have realized was holding you back from showcasing your true creativity.

Similar to Jezebella, I learned that an arrangement on a tabletop or anywhere else should include THREE items, one each:

Tall, fat, and flat.

Works every time.

Unless you are creating a display, always choose storage with doors. No one should have to look at your electronics, old paperbacks, cds, magazines, and dvds.

Here is my design company's philosophy:
"Have nothing in your house that you do not know to be useful, or believe to be beautiful"
William Morris, 1882
I specialize in Manhattan apartment renovations, where space is always at a premium, and paring down of stuff is a necessity. One of my clients actually cried when she read Morris's simple, powerful truth...
Kittie Lonsdale
Lifestyle Space Design

several examples of the "rule of 3" above, 50's pam and jezebella.

odd (3/5/7) is visually more interesting than even (with the exception of 2, true symmetry).

1) Don't confuse lust with love at the intersection of need vs. want (... edit. edit. edit.).

2) Add a dash of color whenever possible.

3) Jezebella, yes "spiky, roundy, floofy" works just about everywhere. Heehee. Different textures are important (especially if you're working monochromatically).

There's no such thing as an ungly color...just color used in an ugly way (this keeps me brave, yet cautious)

...I also subscribe to the rule of happiness in my habitat. There should be something in every direction that brings you joy and warmth, whether it's a meaningful bit of art on the wall, a memorable piece of furniture or photographs of happy times.