Either walk or a car ride from Arusha to Momella Gate, in Arusha National Park. The road to the National Park starts at a village called Usa River, and the Park Gate is about 30 km away from the main road.
First day is a long walk from Momella Gate to Miriakamba Hut, crossing a first section of savannah and tropical forest afterwards. No special problems, for there is an excellent trail and the ranger goes along with you. There is a variant going through the bottom of the valley, on the left of the ridge, which can be a little longer and leaves most of the climbing for the final sector before Miriakamba.
The second day starts through tropical forest, following the same trail of the day before, and becomes steep quite soon. No technical difficulties, though some people might begin to be short-breathed because of the increasing altitude. After about three hours, the forest begins to be clearer in the vantage point known Ngongo Wa Tembo and soon becomes a bushy terrain. The last steps of the stage reach Saddle Hut (3570 m) walking on sand and ashes. From Saddle Hut you can reach the summit of Little Meru(3800 m) in about one hour and a half.
The final climb gets through bushy terrain to Rhino Point, still walking on volcanic ashes. At Rhino Point you start walking along the ridge with a couple of easy climbing steps, about two or three meters high each, with excellent rock without any technical problem. All the path is properly indicated by green paint marks, and surrounds the rocky needles mainly by the side opposite to the crater. Those areas become a little denser in loose stones and it might look as you'll never end climbing that ridge. But never give up. In 5 to 6 hours after leaving Saddle Hut you will reach the summit. It is marked by a Tanzanian flag and can be seen before reaching it.
No need for any special equipment. Walking poles may be useful, and you should have excellent clothing for cold weather on the summit attack night. The summit ridge can be very windy, and in its upper parts a little bit of ice can be found on the rocks. No need to worry, anyway, for the path is clearly seen. A short time after Rhino Point the trail crosses a couple of rocky barriers, but the guides know them. You will never find them unexpectedly and there is no need for climbing equipment.