If you're visiting the parks during the day, get a Stay & Scream ticket if they offer them this year (it's cheaper than buying a ticket on its own). I also highly recommend the Express Passes. They're not cheap, but no matter what day of the week you go there WILL be long waits for all of the attractions, and if you're only going for one night, this will guarantee that you are able to see each attractions at least once. That being said, Wednesdays (if available), Thursdays, and Sundays are the best days to go, crowd-wise. So if you can plan your trip during the week, you'll definitely be better off. Also, the earlier in the month you go, the less crowds there will be.
Once at the event, I would line up for the most popular attraction(s) first (or the ones you're most interested in) to guarantee a shorter wait. That way, if you have the Express, you'll be able to experience at least one or two attractions twice with little wait.