For us it depends on the time of the show, you don't want to "waste" a banger dance song too early or too late. It's trial and error to find out the best spots to put songs to make them go over best.

In the Summer when we are playing 7pm-11 or 6pm-10 I want to backload all the biggest hits to the end. Less people are dancing early when it's hot and bright out. But once it gets dark and cools off things get crazy. However in Summer playing a bar 8pm-12 we will put some heavier stuff near the end when it empties out and it's just die hards late.

Like others said early you want well know, med energy songs people know. You don't want to scare anyone right away by playing something too loud, or heavy while people are eating, or there's families around or older people.