Basic advice, please don't expect some deep, philosophical advice.
Try to limit eating at restaurants and avoid roadside vendors as much as possible.
Acquire basic knowledge of common medicines such as Crocin for fever, Cetrizin for allergies, Ondem for vomiting, and Mephtal Spaz for stomachaches, Pantocid D for nausea, gastric. Ensure to keep these medicines, along with essentials like bandages and Dettol, readily available at home.
Have a good connection with a doctor who gives you honest and truthful advice, never lie to the doctor.
Don't get your eyes checked at a spectacle store, go to a doctor. (ophthalmologist)
Avoid over-eating.
Don't get into the bad books of police, lawyer or any govt official/politician. (or local muscle)
If your gut tells you that something is wrong, it probably is, listen to the gut feeling.
Don't bargain for 10-20 rupees. (not worth it)
Keep cash handy always, have multiple denominations.
Remember some mobile numbers so that you have someone to call during an emergency. (mom, dad, guardian etc)
Don't lie to your family, tell the truth always, it will save you a lot of trouble.
Don't burn bridges due to silly grudges.
Be nice to everyone, be honest, but also remember that a lot of people will try to hurt or take advantage of you so be ruthless and cunning/clever.
Always keep a limit for bullshit, like a threshold, which once gets broken, you voice your opinion and gtfo.
Always keep some identity information on you. (license, aadhar card, pan card)
If some traffic police stops you and you don't want to pay fine, keep 200-300 rupees handy and be polite and plead.
Don't fight with your colleagues at work over work things, not worth the headache.
If someone plays politics to hamper your life, you do the same, but be clever about it.
Always keep a handkerchief on you.
Money is a great manipulator, if you want to earn temporary loyalty use your money.
There are huge margins in selling medicines, there is always room for discount (at least 10%) some stores even offer 20%.
Buy good quality clothes. (brand doesn't matter, quality should be good)
Maintain your calm all the time (even during road accidents), it will help you get an edge over the other person.
Drive at a reasonable speed, accidents are not worth the 2-3 minutes you will save driving fast/recklessly.
Learn the basics of the regional language in the place you live.
Make friends, good ones, who will help you, where the relation isn't transactional.
If I think hard then I can write more, but 26 it is.
Bonus: Don't go into shady areas, don't take chocolate from strangers, read more books, love yourself, exercise, talk to your parents regularly, step out of your comfort zone, spend money don't be a miser you are not going to take it with you when you die.