Modern bedroom designs are clearly different from other bedroom designs because they tend to have clean lines. Neutral background tones that are offset with bright colors and abstract designs from accessories and lighting are also a common trait. Don't let the strong color contrasts and multiple accessories get in the way of a cozy room, though! This is still your bedroom after all, a room where you want to relax before and/or after a long day. It's easy to preserve some tranquility with upbeat modern designs that are striking without overpowering the senses.
When picking out colors, think about what mood(s) you want to create. From relaxing to energetic, the emphasis is much more on mood than matching or sequential patterns. However, that doesn't mean bright purple and yellow will be a good decision! Taking a look at paint samples is always good, and perhaps even looking at the color wheel.
Many people are looking at low-level beds for their modern bedrooms. These beds are based off Japanese/Oriental design and are very beautiful, often carved out of deep colored woods. If you want to add a nightstand, try to find something that will compliment your bed (this also goes for any other pieces of furniture you might have in the bedroom). Also, if you do choose a low bed, a low nightstand is probably a good idea as well so you can reach something easily from your bed.
Besides furniture and colors, you need to have an overall theme in mind. For example, if you want a calm mood, light or deep purples, blues, grays and whites are great as well as minimalist decor. If you'd rather have a cheerful room, yellows and varying decoration would be more stimulating.
The most important thing is to create a room that you will love to use as a getaway. Good luck!