Wall hangings can be tricky though in an apartment. Most apartment managers do not allow any holes to be made in the walls, so hanging a picture or painting with a good old fashioned nail may not be an option for you. For me, all of the apartments I've lived in before, have already had MANY little nail holes in the walls, so I cheat a little and just use an existing nail hole to hang my pictures, or just make a new one...what are a few more little holes and a hole riddled wall anyway? Just don't tell my apartment managers... But, if your walls are nice and smooth and covered in a fresh coat of paint, I wouldn't recommend covering it with nails and fresh holes. There are still options though for hanging pictures. One of my favorite things do with my frames, is hanging the picture with a piece of ribbon, and using a more decorative Command strip hook to hang the ribbon on. Something like this:
Adding wire to the back of a picture frame can also make the picture hanging experience much easier, and you can use a Command hook or two to hang the wire on.
You could also use the Command picture hanging strips, that are basically two Velcro pieces. You stick one strip on the frame, and one on the wall, then stick the two pieces together!
You don't just have to stick to picture frames or mirrors either! Wall decals are also popular right now and there are so many different styles and designs now, it's easy to find one you'd love. They're generally easy to apply and remove, so you can change them up however often you want! I really love the little patterned wall decals.
It's definitely worth the time and effort to cover up those ugly apartment walls with beautiful things you love!