The key to fresh design is to think very carefully about where to put what. Luckily, this can be done no matter what your budget. Editing your rooms really means arrange, reorganize, correct, remove, adapt, change and reorder. Besides creating terrific "new" rooms, editing can be a cleansing process when you give away, trade away or take away household possessions.
Look at your space as though you were looking at it for the first time. Study the floor plan. Ask yourself, "What if?" How do you use your formal dining room? Could you turn it into a sun-room? How often do you use your guest room? Could you turn it into a library with a closeted blow-up mattress for the occasional guest? Once you have established the purposes of each room, try the following.
Take everything off the walls, shelves, counter tops, tabletops. Glean what you can from your cupboards, garage, and yard. Put all these things in one area. This is your "inventory" as you begin to decorate your house.
A good place to start is with a thorough cleaning. While you are at it, you might want to freshen the paint. Now you really have a blank canvas. Don't be scared. I've done this many times and you'll be rewarded, I promised.
Next, arrange your large pieces of furniture. If you feel stuck with some of it, it might just need a slipcover or a throw. Slipcovers are surprisingly easy to make. My latest was made from an old bedspread. Believe me, if I can do sew a slipcover, anyone can. Or, maybe you can trade labor with a friend who sews. Or, maybe you can trade that piece of furniture with a friend who is tired of what s/he has.
Now, it is time to look at your inventory. Gradually bring your pieces in a few at a time. Live with these pieces for a few days. Try them in different locations in different rooms. Take your time. This is fun.
If you follow this process, you should be ready to let go of some of your pieces. But, if you are like me, you might not be "mentally" ready to let go of some. Here's how I solve this for myself. If something has been in the basement for a few years and I can't see where it will fit anywhere in the house, I take a photo of it before I give it away. It's a small thing to do but I can keep the memories and free myself of endless "stuff." Here's an example of a photo of some items recently donated.
Editing really works and may not cost a dime, especially as you work with your own stuff. Believe me, you will fall in love with your rooms all over again.