Use contemporary looking landscape light units for starters. The style and design of the light units themselves can influence the overall appearance of the project. Avoid using the old fashioned lantern style lights or even those common stick in solar lights, they just look dated. Go for sleek designs in chrome or stainless steel. When using floodlights again pick out something that looks nice and modern not the standard black housing that is so common today. Don't forget you will see many of these lighting units, in the daytime at least.
The type of lighting you use can have an impact on the modern look of your design. For example think about LED lights, they simply look modern. LED string lighting can give any garden a contemporary edge. Using some colored lighting can also create the desired effect. Color garden lights can be very effective but care must be taken not to mix vivid colors too much, the effect can look quite cheap. It is usually best to stick with one added color other than your standard white light.
Another way to make things look attractive and contemporary is to use the light units in modern ways. Certain techniques for creating lighting effects have developed over the years moving away from the old light above the front door style. Think about using up lights, down lights and recessed lighting. Back lighting a garden feature is another great trick to keep things looking fresh. Vary the lighting methods and styles but be careful not to over-do it. Sometimes simple and subtle landscape lighting design ideas are the most effective.
Many elements will have an impact on your overall garden lighting design. Something as simple as choosing modern looking units can do the trick. For the best results aim to mix modern looking lights with a few contemporary techniques. If modern is what you want then start thinking in different ways from the start, avoiding the older traditional ways of using outside lights.