Hey Wanders, If you are planning your trip to Shimla then you should check out last video of mine which is Kalka To Shimla toy train experience after that watch this vlog, in this I covered Shimla only in one day as I had only a day to explore Shimla.
so I suggest if you have only one day to explore any places not only Shimla any hill station just wake up early in the morning to witness beautiful sunrise which every hill station offers, and start your day early with a hot cup of tea in nukkad with maska Butter :) soak the vibe of the place. also interact with locals to know best place around and walk towards without any google map it is the best thing you can do while traveling, so exactly I did in this trip started my day early and then explored Shimla by walking, talking to locals and had good breakfast at mall road Aashiyana Restaurant which has beautiful view from the restaurant. After that you I went to Jhakoo temple from roapway which is the easiest way to reach but you can walk as well because its only 2.5 KM but as locals said there is a lot of snow so walking can be tough for us but we get down from the temple by walk. it was good though, after that explored local market, museum, art gallery in mall road and sip on coffee Shimla's one of the best cafe wake & bake in mall road itself.
Rest you can watch this vlog and don't forget to subscribe to my channel as its absolutely free :)