This can be a real challenge with all the restrictions imposed for the wall painting and all that. There are a few ways to circumvent the problems and having the rental apartment suit your style without trespassing on the management rules. Using a lot of plants, covering old carpeting with bright rugs and using proper lighting can help to a great extent. Using nice drapes and curtains can change the basic look of the place.
Nice lighting and shades, artwork on the walls that covers any old patches and marks on the wall can do wonders for the look of the place. getting furniture that not only fits your budget but also makes a statement and doesn't throw light on the rental property can also be one way of sprucing up your place. Finding plants or magazine racks or book shelfs that can hide the cracks in the wall or the open pipes etc can help a good deal without having to spend too much