Hi Ollet,
Welcome to our world, a land full of opinion with no set, correct, defined rules! How do you do well at stand up comedy? You tell the best Jokes you can with confidence and presents, and spend a lot of time doing it hoping you can be in the right place at the right time when the opportunities show there faces.
Asking people if they like your jokes is about as productive as asking Alanis Morisette to describe irony!
I have learnt a few things and I spend a lot of time going to open mic comedy nights and there is only one thing that works every time, know your material and practice it until you know it off by heart.
open mic night is the karaoke of stand up comedy, its nothing to do with the real comedy circuit so done fall yourself, but you can fall the audience, be 1000% more ready than you think you need to be, learn your jokes off by heart and learn every word! yes every word! until you can recite your stand up word perfect in front of a camcorder and play it back sounding confident and in charge "YOU ARE NOT READY" open mic is not the place to learn, its the place to go when you think you have nothing more to learn about your 5 minute routine! that's when you will truly learn from doing stand up, you say you are going to be nervous, but make sure you are only worried about how the audience are going to respond not how you are going to perform!
That's my advice, and I'm the most successful stand up comic in the country currently specialising in bad sarcasm and self deprecating arrogance!