Reservation other than swiss pass

Hello Rajesh. You can use the timetable to plan all your trips in detail (enter 'Kleintitlis' to find details on your connection to the Titlis). You may find that traveling to each location from Zurich requires long traveling times. In case you think they're too long, you can consider overnight stays in other towns. If you want to spend all nights in Zurich, try to book a hotel close to the railway station to minimize traveling times.

I think you already found some of the highlights such as Titlis and the Jungfraujoch. If you're in Zermatt and weather is clear, a visit to the Gornergrat can be highly recommended. No, you won't need any reservations if you plan on using regular trains. Only scenic trains such as the Golden Pass require seat reservation in advance.