Working with Mixing

Yep, How To Digital DJ Fast is a great starter (if slightly dated where gear and software is concerned, but that takes nothing away from the skills needed and taught).

Frankly, Ian, not only is option 3 cheating (you could just mail them your mix and have them play it, no need to have you there), but as Terry_42 says, being a real DJ is “KNOWING what must come next”. Why? Because knowing that means you can read a crowd and are able to move them in a direction that will have them continue to have a great time. Mixes prepared in advance don’t do that. Let’s say you have a few rap tracks in your mix. At the moment the first rap track drops there is 20 people dancing. The rap track drops, people on the floor look at you funny and walk off. Nobody else comes onto the floor. Here your mix continues for 2,3 maybe even 4 rap tracks with everyone looking at you, clearly not happy with the musical choice.
Point in case being that you need to figure out what works and adjust accordingly.

The only way to learn this, the most important DJ skill imho, is by playing out. And I mean playing out, not standing there playing prerecorded stuff. And you learn by playing that rap track, noticing the effect (people looking and sitting down) and deciding that you definitely don’t need another rap track next, but rather finding a way to cut the playing track short or at the very least transition into another genre right after it finishes. It’s this falling down and getting back up again that will grow your crowd awareness and create that knowing what comes next skill.

Remember: “succes is getting up one more time than you have fallen down”. So embrace your “mistakes/failures” as they are the best teaching tools you can get.

I’d say don’t worry too much about your technical skills, but take every single opportunity to play out. Especially in relatively friendly environments like friend’s house parties and such.

Finally a tip on collection management. Think long and hard in advance about the music you think you’ll need. Bring roughly twice the amount of music that you think you’ll need (from 20-25 tracks per hour normally, so bring 40-50 tracks per hours gig). Create mini playlist of 3-4 tracks that you feel go well together and that you have practiced mixing in and out of. Now when you play a track from that playlist and the audience likes it, you don’t have to go digging like crazy for a track to follow-up with, they will be right there and with practiced transitions, giving you plenty of time to think about what mini-playlist to move to next.
This takes away a lot of the stress.

In answer to #1 play,whatever genres you like

The OP was asking what would be the best music/genre to practice on to improved his DJ skills, if he just practiced on whatever genre he likes he would more than likely to find some difficult playing certain genres
Back in the day, the DJ’s taught their pupils started on Classic Disco, which is works wonderfully (for me), I can switch genre from rnb, to electronic dance music, vice versa, with no problem

Fast forward today, most of the EDM tunes these days are very short intro and outro, hard to grisp for a new beginner to practiced on, imo, best way to practiced is with genre from progressive house, anything from Jerome Ismae remixes will do you solid most of his intro and outro and is super long and easy to practiced with, and his tracks loads of fun too