I've been a homeowner for a little over three months and there are a few lessons I've learned:
When you are house shopping, set a price range. Stand firm on it, then double it and find somewhere to live.
Once you've selected a house, take pictures of the inside. They'll come in handy as you plan a decorating scheme.
As you plan your decorating scheme, refer to those pictures. You may remember tan carpet, but there's a good chance it'll be baby blue.
Once you start decorating, don't be afraid to take chances. Kilz will cover anything -- even wallpaper.
Speaking of wallpaper, the vinyl kind may look good going up, but it will be terrible coming down. It comes off the wall in sheets. Of course, those sheets are layers of the paper. The top level is the pattern. The second layer is the backing. The next layer is the goop used to put the paper on the wall. And then there's the final layer. It's sheetrock and I'm pretty sure it's not supposed to scrape off.
As for putting wallpaper up, get someone to do it. However much it costs is worth it -- especially if the process involves any family members.
You can paint over wood paneling, but you can't guess at the amount of paint it will take. Here's a tip: buy however much primer and paint you think it'll take and then buy that same amount again. Then when you have to go back and buy more paint, you won't have to buy as much.
Crown moulding and chair railing makes a huge difference in any room. The chair railing is not that complicated to put up. The crown moulding is tough, unless you use the pre-fabricated corner pieces. Then the only challenge is making sure you don't install it up upside down.
Once you have the trim up, there's one secret step that can make any job look professional: caulk. There's no imperfection in the wall, wood or workmanship that can't be waylaid with caulk.
You can plan the look of a room all you want, but it's not going to matter until you get paint on the wall. For example, let's say -- hypothetically speaking -- your guest bedroom is red and black with gold accents. Painting your adjacent office lavender may look great in the local hardware store, but horrible in practice. (Again, not that I would know, but Kilz will hide the lavender.)
There are a million uses for Saran Wrap, and several of them having nothing to do with food or wrapping a friend's car as a practical joke. You can put paint on and take it off with the clear plastic stuff (Hence, life's rule number 112: Never let your wife watch Trading Spaces or HGTV.) Of course, taking the paint off with plastic wrap will take hours on end. Especially if you are painting in an office that used to be lavender. Or so I've been told.