1. First make sure with your electrician if the power source (the cable that will attach to the steplight) will be mains power (240V) or low voltage (which will require a power supply - known commonly as an LED Driver).
2. Second thing to look at is whether the steplight will be recessed or surface mounted. Obviously surface mounting is far easier to install, however recessed models have a nice flush appearance.
3. Choose the colour light that you would like to see - either a Warm White (3000K) colour temperature, or a Cool White (5000-6000K) colour temperature.
4. Lastly, depending on the area to light up will determine the size of the light and the wattage.

So before you buy, think of these points. It will drastically speed up your search time to find the right steplight.