A handful of small things that make the first few days easier. None of it is complicated.
100 rupees is roughly one euro. Cards work in hotels and bigger restaurants, but it is handy to have some cash on you for tips, small shops, autos and the bazaars.
Get it from an ATM once you are through arrivals. The first machines you pass are often busy or out of order, and there are more of them further along and outside the terminal. Most ATMs cap a single withdrawal at 10,000 rupees, so 5,000 to 10,000 is a sensible first pull. The exchange counters in arrivals give noticeably worse rates than the ATMs.
Tipping is normal and appreciated, and the amounts are small. For a small service, 50 to 100 rupees goes further than it sounds. Beyond the two below, trust your own sense of when someone has looked after you.
Nothing here is cause for worry, and the food is one of the best parts of the trip. A few habits are worth having.
If your stomach does have a rough day, electrolyte sachets and rest sort out most of it, and there is a pharmacy on more or less every corner.
Uber is the easy option, and the account is worth setting up before you travel rather than on arrival. See Travel info for how, and for when you will need it.
Nothing here is a rule, and nobody is going to mind what you wear.
The one thing worth knowing is that outside hotels and tourist sites, sleeveless tops and shorter skirts are less common than at home, so in the old city bazaars you may notice a few more looks than you are used to. It is a question of feeling comfortable rather than of doing anything wrong. If you would rather not have that, a top with sleeves does the job, and a scarf or stole draped over the shoulders works just as well. Monday morning's shopping trip is a nice moment to pick one up if you fancy it.
At a couple of the sightseeing spots, and at the Shiv temple in Kasauli, covered shoulders and knees is the kinder choice, and shoes come off at the entrance.
At Khas Bagh and at the reception, wear whatever you like. See the clothing guide for the wedding days.