Generally apartments have white walls. I would choose two colors - a deep color and a bright one, such as navy blue and lime green and try to use those for furniture and accessories. Coordinating your colors gives your place a decorated look. Limiting your color palette makes it easy on you. In my first apartment I used those cotton bedspreads from India to set my theme.
Sheets serve the same purpose.
For that matter any inexpensive fabric that is easy care will do. Put something dramatic on the walls that echoes the colors of your fabric. Back in the early 70s a lot of us were stretching Marimekko fabrics over a wooden frame and hanging them as instant art. If you don't have building skills, but a cheap picture frame at a flea market and staple the fabric to the back of it so that it is stretched taut. Or collect a group of old picture frames, Hit them with a blast of spray paint and put mirrors in them.