I don't know what you know already, so please forgive me if any of this information seems redundant, but here are the basics of what and why:
1) a SOLID mixer that you can play on. It is the heart of your sound, and if it doesn't sound good, none of the rest of your gear will either. If it's flimsy, it will break on you, or you will be afraid to actually play on it. Preferably one with faders, but I used a 1202 on tour for years and made it work, though I wish I'd had something a bit nicer. Don't underestimate its importance, and though most this side of the pond don't realize it, or treat it like one, it really is a powerful possibly your most powerful instrument.
2) a SOLID drum machine whose sounds you won't get tired of. When it comes to techno, you can't go wrong with a 909. I've only used the real one, but a friend with both that and the boutique says the boutique has the sound well enough that you're not going to be able to tell the difference unless you have them both side by side. So the tr-09 is a safe bet. The tr-08 is also an awesome tool. Personally, I may go with a combination of the TR-08 (because I like the hats and snare better), and a Volca Kick (because you HAVE to have The Whomp to make Techno). A sampling drum machine is also a good bet, because as long as you dig the interface, you will never have to get tired of using the same old sounds, just cook up new ones any time and load them in.
3) a SOLID synth. When you play live, that synth will be your signature, and how you play it will be what makes or breaks your set, as a performer, so one that YOU can get around in quickly, and whose tonal character never gets old is the kind of thing you're looking for, and it might be something few people use or dig, but you manage to get ill with. For example: a JP-8000. I can't stand the fucking thing myself whenever I have tried to play one, and under any other circumstance dislike the tone, but one of my best friends has utterly mastered that thing and can pull the most jaw-dropping sounds out of it at the drop of a hat (or tab, for that matter). For me, it's my Evolver, though it used to be my Pulse+. Any time I need to cook up a distinct sound quickly, and software just ain't doing it, that thing is there for me.
3) a decent sampler. You're going to need more sounds than just your drum machine, and one synth voice, especially for longer tones and loops, but also for drums, percussion, bass, melodies, and other personalized sounds that will also show the audience why it's you on stage and no one else.
4) a SOLID sequencer. One that has a workflow you can enjoy, with ROCK SOLID TIMING. Honestly, Techno is about totally solid timing on all of your sounds and The Whomp. I used a pair of MMT-8's for years, now I use an MPC1k, though I will probably ditch it for a Pyramid (to drive a very small Eurorack rig, when I can marshal the spondulix). You probably will want something that will send multiple tracks on that you can mute and unmute at will, handles a fair amount of info, maybe even sys-ex, depending on your synth/s, and even better if it can handle more than one group of sequences, and lengths at the same time, as this will help you in making transitions between chunks of ideas in your set.
5) a couple of effects. For years for me, it was a few guitar pedals. A Rat, an analog delay, a digital delay, and an envelope filter created tons of fun, playable variety in my set, because they were easy to use, sounded great live, and worked well with my mixer. Really, sky's the limit with those things.
*Optional, though strongly suggested: a good EQ, and a SOLID dummy-proof but good sounding compressor. The EQ is to shape your sound for the room (though you will ALWAYS want to speak with the house engineer first, and work things out during sound check), and the compressor is to beef out your sound as well as avoiding catastrophic failure of the sound system. Trust me, I've blown a lot of drivers along the way to learning the importance of this lesson. These days, I use a DBX 166, because it's simple, I can set it and forget it, it works, and it's not irreplaceable.
As I said, these are the basics, and you can slim things down by getting pieces that will run double duty, but you can see that there are a jobs that need doing. As mentioned earlier, Headless Horseman gigs with just a pair of Octatracks, an Eventide Space, and a mixer, and his sets sound great, though maybe a little one-dimensional tonally.
Things to consider are first and foremost how YOU play with each piece, how you get around in each, and how much enjoyment they give YOU, because that is going to come across like nothing else when you play. I've heard folks with some of the jankiest, shitty sounding gear pull off some of the most fun, entertaining, expressive and inspiring sets because they had awesome ideas, and knew how to get the best out of the gear they had. Don't worry about getting the latest and greatest, regardless of what other folks are hot on. (except MC-303's, those things just suck ass, no matter who plays them.)
Practice PLAYING, and do it A LOT if you plan on ever playing anywhere but in your own room. Don't practice producing, just play, and play something different EVERY time. Sure, practice each part until it sounds like you want it to sound and you can execute it correctly and consistently, but do something different each time, like mix and match parts you've never played together, try different effects, and break out of the formula that DJ's always stick to. Remember, it's NOT a recital, you're not DJ'ing, people are not there to see you DJ or play the tracks you've made just like the recordings you've released, you don't have to worry about the record running out in a few minutes, you have all the time you need, and you can switch things up as much as you'd like, this is YOUR set. Be you doing you, and be good at it.
Ok, if you've actually read all of this, I commend you, and wish you the best of luck.