Just because you rent doesn't meant you can't make some big changes to your space. Check out Apartment Therapy's round up of easy decor ideas for a rental that you can take with you.
Change out the showerhead so you can get a shower with the amount of water pressure you want, not whatever the landlord installed 10 years ago.
Hang pegboard in the kitchen to put pots, pans, utensils and more on. Try painting it for even more impact, and when you move, it's easy to take down and move to the next space.
Temporary wallpaper is a great way to make a huge impact but get your deposit back.
If you hate the builder grade light fixture in your apartment, go ahead and change it out for one you love. Just remember to keep the old one so you can replace it when you move.
Finally, trade out the kitchen knobs for some that make a big impact. Just make sure your old hardware's easily accessible for when it's time to move on to the next apartment.