1. Examine what you already own before you buy anything. Anything and everything can be decorative. Things like post cards, old calendar pages, jars, vases, books, and collections work really well. As well, take a certain object (like post cards) and type that into the DIY section of Pinterest and watch all the cool projects that pop up that you probably haven't thought of to repurpose what you have.
2. View everyday objects in new ways. Instead of hiding things like jewelry, shoes, cosmetics, and accessories away, select some of your current favorites and mix them into a display. This is great as well because it allows you to change things up frequently and you can also do it for seasons/holidays. In the fall I had all of my sunglasses on an Ikea cake stand. It looked fun and I knew where every pair was when I wanted to wear them.
3. If you spend money do it sparingly when a space is not yours. * I find that money is never wasted on flowers and greenery. Fresh flowers around the house elevates a space immediately and allows you to inject color into a space with no commitment. If you aren't down with flowers then succulents, ferns, or creating a terrarium are all great touches.
* Get personal photos printed in different sizes to make a gallery wall.
* Visit second hand stores for vintage or antique pieces.
* Purchase some supplies that will help you create DIY projects in the future.