Social Ettiquette is a pain in the ass for ISTP's. It drains our energy. There are 2 ways you can percieve social ettiquette as an ISTP: you can think about it robotically and deploy known techniques... or you can be insecure and try to match everyone's societal expectations.
An insecure ISTP is one that is worrying about what other's think. Our capacity to please others is so small that it is actually bad for us and half of the time will yield negative results when we DO try to do something nice for someone else. When you worry about what other's need, that's your Fe clinging to you for dear life. Put that child back into its car seat, and engage your eyes. Look around. Use your Se to see what everyone else is doing. Then do that.
We use our Se for social ettiquette as if it were a martial art. If someone gives a complement, you reply with a canned line that you've practiced in front of the mirror such as, "Oh thanks, you too" with a nice big smile! The great part is, 90% of the time no one gives a damn about the content of your words, they only care about the energy that you radiate. ISTP's usually don't radiate much energy. In fact we usually drain others when they look at us.
ISTP's have one ounce of enthusiasm per day. Once we use that up, we're pretty much done being nice for the rest of the day and need a nap. Ever suffer from an energy drink crash? That's what we feel like after we've been nice for too damn long. Know this. The majority of people you talk to don't give a damn what words you choose, they will only care about the energy and enthusiasm coming out of your voice. Why do you think ENFJ's are so loveable while simultaneously cynnical? Its because they make everyone around them feel super dooper because they have entirely too much energy.
So go to a party, give giant loud "hello's" and be sociable. Ask people questions about themselves. Its the hardest thing to do in the world when 50% of the time we already know they're going to bore the fuck out of you. But that's how you get people to like you. So if you don't have the energy, drink a red bull before going to your friend's wedding.
Its a long drawn out process and involves a lot of mistakes. There's no way you can prepare for it. We can think about the logic and theory of things all we want, but execution is a completely different story. So get out there, be completely awkward yet sociable. Here's the thing, you can be as awkward as you want, but if you show a genuine interest in someone else by asking them questions about their life, they'll usually excuse your social ineptitude because they're just happy that someone in the world wants to hear about all their damn problems!