Start with fresh pastries, omelettes and good coffee at Sakley's — a popular café near Mall Road; a reliable place for a filling breakfast before sightseeing.
Visit the hill-top Naina Devi Temple for views over Naini Lake and then walk Mall Road for local shopping and the town vibe; Mall Road stays lively most of the day (shops usually 9:00am–10:00pm).
Rent a rowboat or paddle boat to experience the lake from the water — one of Nainital's classic experiences; typical boating hours ~8:00am–5:30pm, weather permitting.
Visit this small high-altitude zoo to see Himalayan species such as snow leopards and Himalayan bears; open roughly 9:00am–4:30pm so aim to arrive by mid-afternoon.
Walk the lakeshore and visit the small island with the aquarium (aquarium and island activities typically 10:00am–5:00pm); peaceful boating and birdlife make this a relaxing stop.
Explore easy trails and viewpoints around the lakes; late afternoon is often best for bird activity — Sattal is technically open at all times though facilities operate daytime.
If you want a thrill, book a paragliding or zipline session from local operators — many run between 9:00am–4:00pm but require advance confirmation and good weather.
Visit Chauli Ki Jali for dramatic cliff-edge views, rock climbing and paragliding take-off points; viewpoint is open all day and is spectacular in clear weather.