1. first of all, as you sow, as you reap. treat people nice and you'll be treated the same way. no matter where, people deserve polite attitude from others. don't treat the airport staff as 'mulla dhoti', respect them. you'll be treated nice too.

2. do not lock your luggage. yes, though sounds weird, DO NOT lock your luggage. it gives an impression (to people who really steal things and give a shit not about morality) that the bag has something valuable. same thing in nepali airport too. never lock your luggage. if possible, carry all valuables in carry-on. put socks, kattus on top of other things in the luggage.

3. for long transit hours, you can actually enjoy indian airport much more than other airports. why? you know the language, know the money, know the food, etc. they also have business lounges for sleeping, but you gotta pay.

there is no horror in going through indian airport. i have been there a few times already and so far, no harassments. actually, i find the people there very friendly and willing to help. just put a smile on your face while approaching anyone.

good luck on the travel.