Hi Aftab!
Unfortunately, Bangalore isn't Observational Astro friendly anymore. Earlier, it used to be from November/December until April. But extremely unpredictable nowadays.
But suddenly some days are good in any month. So keep an eye on weather forecasts for the week. Generally monsoon, both the regular and return aren't good times.
Late night/early morning is a good time.
Avoid times close to full moon. Before and after. No Moon (Amavasya) time is the best.
Chose an area that is more prone to dry weather.
Planets like Jupiter and Saturn are in the skies for a long period and are visually beautiful to track. Track other planets on Stellarium, which you can download on to your computer.
Constellations are in the skies for usually almost 5-6 months, all moving from East to West.
I don't know about Kavalur, but near it there's a place, which is open to public, at a cost. It's a hotel/ camp kinda place.
Also Yelagiri, has good viewing sites.
I'm very much an amateur amateur, so hopefully more senior people will answer your queries!
Aĺl the Best for Clear Nites!
Leela Kalyanaraman