all i can help with is what i've learnt over the years but i'm faaaar from perfect in my mastering....
the single biggest factor that helped me get my mastering better (without having to guess and fanny around all the time) was the acoustics of the studio space. i made a huge bass box for the back of the room out of lead sheeting, bass traps, everything. besides we made the rooom ourselves, so we made it like a room within a room. my decisions are now really ****in accurate...
the second i would say is to stop experimenting all the time and start to think long and hard about the chain. use tried and tested theories.. first eq ya shit using a spectrum analyzer. sure, trust your ears in certain bit but get the hell rid of those lows that will drive the other things in the chain that dont need to be driven (BTW one thing that might be contributing to ya boomy mixes might be the fact you're not rolling off @ 38Hz). bring those highs down that are obviously too hi... then it's pretty standard - get the level up to zero, then compress, then limit - both multiband (dont forget to use filter's to understand what each band is doing!!!!) get those attack/releases right too for each band for your music.. one thing that helped me NO END when realizing this was when i spent a whole day out of the studio with a pen, paper and the internet and constructed my chain. if you do this, you're not in the studio getting distracted and you can really understand what needs to be done...
it's really funny actuallly but i go back through my unmastered stuff these days and i'm like - how the HELL did i get that so wrong in the mixdown stage!?!?!!! but it's human nature - of course your ears are gonna get shot, you're gonna put in that hi hat that's just that little bit too hi and then before you know it, 10 minutes later you've eq'ed everything else to fit with it and messed up the sound. the key i feel is to leave your studio session thinking - it's a track!!!!! then go back to it and with the correct mastering you really can make ANYTHING sound good - as long as you left that studio session 100% sure it was a track...
you see that's the thing about techno.. there's no rules because you don't have to have set 'clean' sounds in certain places in the mix... whereas if you were making pop track i really would expect it to be pretty much 100% before mastering, just a few cleanups, techno is very different.. the very fact it's a weird eq before mastering can actually make it sound very innovative and different after mastering..
hope this helps and you see what i'm saying mate :)