So yeah, not to toot my own horn or anything, but I'm pretty decent at decorating in SL.
People who come over always say my rooms look good. When I show pics of rooms on Flickr, I get favorites. Certain people are jealous of how I have made a home. I've styled rooms for vendor ads. I even managed to get one of my bedrooms into a magazine. After years of wanting a skill in SL, this seems to be mine.
But I used to suck at it. Oh how I used to SUCK at it. I even lived in a furnished skybox for a while because it was way better for someone else to decorate than for me to do it. My decorating consisted of putting down a plant and putting pictures all over the walls. I never knew exactly where anything should go and so I'd either buy a set and set it exactly down the way the ad looked, or I'd just kind of throw things in a room, close the door, and sit outside.
However, I'll tell you a secret. It's easier now to decorate your home in SL than it ever has been before because there are so many fabulous decor creators out there now! Seriously, there are soooo many good places to go.
So here's what you do. First, go to any/all of your favorite furniture stores. Here I am at LISP Bazaar!
BUY ALL THE THINGS!
No really. Buy everything! Buy anything you can get your hands on! If you think you like it, GET IT!!!
The real "secret" is this: The more you have to choose from, the better you can decorate simply because you have enough to choose from! It's easy to decorate a bedroom if you only have one bed, one matching nightstand, and one matching rug. But will it look GOOD? Will it be the kind of room that people exclaim over how it looks? Probably not. But if you have 10 beds, nightstands, and rugs, plus a lot of other things, you can mix and match and make it yours.
Oh. But if you really suck and just can't do it, IM a friend and ask them to help you. That always works, too.