Lighting steps for safety is an obvious requirement in any garden, but functionality can be coupled with decorative merit if the lighting is subtle - picking out texture and colour of treads as well as highlighting their location, for example. Cross lighting steps from flanking walls is one of the best techniques: recessed steplights, using 20w dichroic reflector lamps to project beams across a staircase "graze" across the paving to display texture and colour as well as illuminating the treads and risers. Steplights with a plain rim can be used if you stick to a 10w lamp or, better still, a 2w l.e.d. (light emitting diode) lamp - you have to remember that these types of light are essentially recessed spotlights and can cause glare if used carelessly, so they should be used with a frosted lens or glare louvre option for this reason. Lamps of more than 20 watts are seldom justified - wide beams are usually best to make sure treads and risers are most evenly lit, unless you need to project a narrow beam across treads of wider staircases in a formal and symmetric setting.
Recessed "Eyelid" steplights hide the light source from view if you are walking past. Elipta's 12 volt recessed steplights can all accept the MR16 clip-on frosted lens (fitted onto the front of the lamp) or the Elipta honeycomb glare louvre which is designed to cut out stray light. A glare louvre is an expanded metal mesh in a honeycomb pattern that stops you seeing the light source outside the beam angle of the lamp inside the light. Alternatively you can fit a reeded "spread lens" which literally spreads the beam from a round one to a more rectangular shape for wider coverage. "Smoothie" steplights live up to their name by concealing all fixing screws - the light slides into a recess tube set into the wall. Smoothie steplights are available in both 12v and 240v versions with plain rim, eyelid or grill fronts in stainless steel, copper and brass.
Make sure that any steplight facing a terrace, path, window or other viewpoint is of a low glare type, preferably a surface mount type using a capsule lamp or shielded l.e.d. lamp rather than a reflector lamp. The E2161N eyelid step light, available in brass, is a good low voltage halogen choice and now has led options. Elipta's 1 watt l.e.d. Navigator Eye is an excellent choice for lighting small step areas: this miniature steplight has an eyelid hood, is available in stainless steel or copper and offers a choice of white or warm white l.e.d. “Waymarking” steps with lights set into treads is an alternative way of identifying the steps in a garden which also has ambient light from other sources, often using other models from the Navigator led range such as the Maxor
If you don't have flanking walls from which to light steps, or trees and structures on which to mount downlights of one sort or another, then you could end up using bollard lights or spreadlights to fill in - see the page on "Paths and Drives" for more suggestions.