Fireworks - will I ever figure out the best settings?

At the end of the Fair there is a fireworks show.  SO I have the opportunity to photograph fireworks several times a year thanks to where I live - on average I have 3-4 shows to 'practice' on.

Here are my favorites from this year.  We were watching from about 1/2 to 3/4 of a mile away.  Unfortunately I was in a store parking lot so there was light pollution from behind me while photographing these, plus traffic on the road in front of the parking lot.  It was minimal, but did over expose a few photos.

I used a tri-pod with my 55-250mm lens with an ISO of 800 on the best shots.

ENJOY the show!