Once you find the DJ or DJ company you are happy with, these are a few tips to make the night be fun for everyone, including yourselves.
1) Have one point person for your DJ. Whether that is you, your new spouse, a family member, it doesn't matter. When it comes to the dance and any garter/bouquet tosses and changes, tell the DJ directly. Don't have some random person or groomsmen change things.
2) Don't lock the DJ into a playlist of songs the bridal party likes. Always let the DJ take requests. Playlists tend to push those who don't like the music off to the bar (or they leave early). Even the Top-40 version of Gotye's "Somebody That I Used To Know" isn't danceable.
3) Just because you don't like group dances (electric slide, cha-cha slide, cupid shuffle) doesn't mean your guests don't either. Keep an open mind. But keep in mind, you don't have to dance to everything the DJ plays but you want people to stay out there to have fun.
4) Tipping: I have advised friends to implement a sliding scale and tip based on how it went, but at least let the DJ leave with $10-$20 (if you don't include them in dinner, this can get them something from the late night Wendy's drive thru). I suggest starting an envelope with $200 in $20s and slice off as you determine appropriate. The better your DJ does, the more likely you don't take money away.