those are some big questions, and the answers are going to be very different depending on what you want to do.
Where do you want to get booked, a restauant, a birthday, what type of gig.
It really depends on 1. Very different things for different age groups. Things you know inside and out so you can foucs on connecting with the audiance.
Again, depends. If you're just starting out you dont have that mudh of a reputation, start low and really just discuss it with who ever is going to be potentially employing you. I remember when i did my first restaruant gig I was getting 100 bucks a night, magic for about 4 hours. Now i charge more. Birthday parties and other things are different too because it's a different style of magic.
PRACTICE, paractice, PRACTICE. The only way you're going to improve is to go out there and do magic for people everyone, and everywhere. You will mess up, but when you do it's good practice for covering your ass. Even professionals mess up from time to time, they just know how to make it look like they meant to do that.