Question

How do you write good dialogue?

Answer 1

1.) Listen to how actual people talk
2.) Figure out the flow of your dialogue
3.) Pattern out the information
4.) Write the scribble version (very rough draft)
5.) Write the nice version

Answer 2

But what if I can't seem to do it right and it never seems to make sense?

Answer 3

How do you start it off or bridge gaps between conversations?

Answer 4

It depends on the setting, plot, and reason behind the dialogue. What are you writing it for?

Answer 5

Write it in the vernacular. Leave out the parts your reader doesn't care about (Like "Hey what's up" "Nothing" "Okay") You'll notice these pointless conversations are absent from most fiction.
Try to keep it natural.