Correct me if I’m wrong, but it sounds like maybe you haven’t DJ’d at too many weddings? If so, whatever you do, don’t overestimate how easy it’ll be. Wedding crowds don’t care about how great your taste is, or whether you have the newest underground tracks. They (for the most part) only want to hear what they hear on the radio. Even if you have the latest Justin Bieber album (just for example), people will only be familiar with what has been released via the radio and/or music video. Which brings me to my next point, you have to have EVERYTHING. Realistically you don’t actually have to have everything, but everything they’ll ask for. While a lot of wedding DJ’s in my city boast 15,000-20,000 track libraries, I only have a playlist of approx. 3500 that I use for weddings. I’m always updating and adding to it, but I’m at the point where I have a pretty hard time thinking of what I need that I don’t have, and 9.9 out of 10 times, I have what people are looking for. Even though I download the latest tracks from my MP3 pool, 95% of the request are driven by older music, like retro eg: Michael Jackson, Madonna, etc…And it’s not surprising since most people that get married are between 25-35 so they know what they know and that’s what they want to hear.
I wouldn’t bother trying to establish a “no requests rule”. Nobody will follow it, and if you don’t have what people are looking for, some of the more rude guests might not hesitate to make you feel like crap. When I started doing weddings I got all kinds of comments like “what kind of DJ are you?!” and don’t think because they’re your friends that you know their crowd. There’s likely to be a bunch of people that they don’t know (or maybe don’t like)…And why wouldn’t you want to play requests??? You want everyone to have a good time right? Imagine if you went to a party and the DJ played everything you ever asked for, I bet you’d love it. I would too, except since I know what it’s like I would rather not bother the DJ. As for the flow between different BPM’s, I wouldn’t waste my time trying to figure out how to beatmatch 90bpm hip hop with 130 bpm LMFAO. Just use a delay, or play the song almost to the end, and come in hard with a dancey bass beat while quickly (but not abruptly) pulling the fader down on the hip hop. There are some tricks you can use, like quickly increasing the tempo on the hip hop song to match a quicker BPM, but you really have to know your music, or have some preset songs lined up which doesn’t really align with “taking requests”. Sometimes if it’s obvious people don’t like the track you just put on, do a quick spin back (practice if it’s something you don’t usually do), and throw on the next track starting with the beat.
As for the slow songs, I try to never play them. The only time I’ll put one on is when the dancefloor is empty. If you have 3-4 people dancing, a slow jam is sure to get at least 4-5 couples back on the floor, especially the wives who claim their husbands won’t dance with them unless it’s a slow song. Dancing fast requires a certain degree of confidence (rhythm also helps), while slow dancing is something anyone can do so it’s no surprise that people that won’t dance can be convinced to slow dance. Then when it’s over, come back in with a bang.
If you can think of a way to copy the text from an itunes playlist and copy it into a word doc. I’d be more than happy to share my playlist with you. I’ve been doing this for 20 years.
Most of all, have fun. I’ll be honest in saying I can’t stand commercial music to any degree. I love indie, and indie electronic. I don’t even practice with commercial music at home. But you hear it everywhere, so it’s impossible to not be familiar with it and remember where all the breakdowns and melodies come in. Despite this, I always have fun working the crowds at weddings, and it’s effortless to get someone that says “YOU’VE EXCEEDED ALL MY EXPECTATIONS OF A WEDDING DJ!” which makes it all worthwhile.