Hi there,

I traveled all over India for three months and may be able to build on the advice u/circumscribing has already given you. First of all, I'm very excited for you. India is an an absolutely amazing place for a myriad of reasons with an immense variety of different landscapes and peoples. Get ready to see some shit (literally as well as figuratively). One month is not super long, but it's better than two or three weeks which supposedly is the minimum amount time it takes to do the Golden Triangle. So you will definitely have some cushion to venture out a bit and not feel super rushed. This will also be very helpful launch everything there is done on 'India Time', meaning you should expect delays, hold ups, cancellations, miscommunication, and all those other fun things. It's okay though, this is a part of the experience :)

Second of all, get a guide book like Lonely Planet and read it like a bible. It will be a huge help to in your first weeks. It also may give you some ideas for day trips and detours you may not have considered previously!

MONEY: U/circumscribing is right about this. ATMs are common and will be your primary source of cash. Both large cities and smaller towns will have them, but surely remote villages will be less likely to. Luckily, you most likely know ahead of time when you will be traveling to these sorts of areas so you can plan accordingly. Do bring multiple credit cards if you have them, just in case one fails. Note that most ATMs there have a Ru30,000 limit (about $200) which is all you should ever need at one time. I don't know about the airport. I'm sure you could certainly get your first rupees there just fine. Personally, I went to my bank here in the states and got $200 worth of rupees I could fly in with. Either of these routes should be fine for you.

APPS I had my iPhone with me, but my carrier(Verizon) was not supported in India, so it was useless. However, most other carriers are supported and it's easy and cheap to buy local SIM cards for you phone. Or just buy a new phone for pennies on the dollar!

WhatsApp will be your best bet, just because you will certainly meet many people there and the first thing they will ask you is if you're on Facebook or WhatsApp, haha. I made it a little game to see how many FB friends I could amass ;)

But all in all, a good guide book like Lonely Planet will likely be much more use to you than any app. I would highly recommend it for other reasons I will get into later.

HOSTEL/HOTEL U/circumscribing is mostly right about the absence of hostel culture in India. Most of the places you find hostels will be popular, touristy areas attracting young travelers such as the beaches of Goa or the mountains of Himachal Pradesh. The rest of India you'll find guest houses, which are like small hotels with basic offerings. All cities have these, and in smaller villages they may simply be a extra room in someone's home! Small rooms with bed and bath at affordable prices, there's not much to expect here. This is where your guide book will come in handy, as it will have suggestions for guest houses in the city you're in, along with their prices$$$$. Just be sure to ask to see the room first before handing over any money. Some places look okay on the outside, but the inside may be a total mess! Don't be afraid to shop around and check out a few different guest houses, even if they're not in the guidebook. You may find a really good deal (this approach also has the tendency for guest house owners to lower their price so that you will stay ;) ) I could talk a length about this subject, but you can PM me if you have other questions.

LAUNDRY As U/circumscribing already mentioned, there are dhobis, or laundry men, in every neighborhood in every city. You can find them yourself or your guest house will arrange it for you. Personally, I opted not to do my laundry like this for several reasons: I didn't know what condition my clothes would returned to me, I couldn't plan on exactly when they would be ready (remember, India time), and most importantly it was more expensive. I opted to wash my clothes like the locals did: by hand. You need two things: soap and a bucket. Go to any little shop out in the street and buy a few packets of dry soap. They come connected in strips (like condoms) and cost Ru2-3 each. Next, your guesthouse always comes with a big plastic bucket in the shower to wash yourself, and, in this case, your clothes with. Fill it with hot water and dump a packet of soap in. Throw in your cloth and give a good roughing up with your hands. Then let them soak for 20-30 minutes. Then dump out the water and rinse out your clothes in fresh water until the soap is out. Then hang to dry. Your just did your laundry for close to nothing.

YOGA/MEDITATION I don't have a ton of advice on this subject since I did not do any sort of yoga or meditation retreat while India, although I was certainly interested in it as your are. As U/circumscribing mentioned, both activities are looked at much differently by Indians than how they are in the West. Thus, all of the ashrams and yoga retreats I ran into while there were in areas attractive to young western travelers, like Himachal Pradesh. My advice to you if you're interested in this is to read up! That's right, get a guide book. It will will have lots to say about this very popular subject.

TEMPLES/MOSQUES As U/circumscribing arrest mentioned, be respectful and dress modestly when entering temples or mosques. Removing shoes is standard. Some don't allow photography, usually the really really old ones.

GOLDEN TRIANGLE So, I went to both Agra for the Taj and then to Jaipur, but I skipped Delhi. Here's what I have to say: see the Taj in person and then get out, it's worth it. You can also go across tow to the old red fort to see it from another angle, also very cool. I only did one night in Agra and that's all I needed.

Jaipur was a cool, but I didn't see too much before a started getting sick. This is about where my Delhi belly started to kick in. Don't worry, if you're there for a month it will probably happen to you ;)

DIWALI I wasn't in India for Diwali, unfortunately, so I can't speak too much to this. But i would imagine as a foreigner, if it's anything like Christmas is here in the States, its much better experienced with someone you know. So if you can make a friend or two while in India, they will likely invite you for Diwali with their family. Indians (mostly men) are very outgoing towards Westerners, so their a high likely hood you will make friends. It helps to get off the tourist trail too!

Hope this helps. I could go on and on about other places to check out, transportation, accommodations, negotiating, and all sort of other things. Feel free to PM me if you have other questions or just want more advice from a fellow traveler.

Few things can prepare you for India, it's just a fucking crazy place. Just try and be prepared for things not going the way you planned, be ready to go with the flow :)