My band plays some ambient / post-rock stuff and i recorded our first ep a couple of months ago. Here are some tips
Drums:
Room mics and overheads! You'll want a lot of air in your music and a verby drum is the way to go for post-rock. Just listen to EITS, you'll want that drumsound

. close mic everything though, but make sure the snaresound is coming from the OH's.
Don't filter the OH's too much. keep the HPF at 200hz
Use little compression but make them sound punchy
Bass:
I like slightly distorted bass tones but it really depends on the style of post-rock that you're recording.
Guitars:
Cleans: I like convolution verbs on the clean guitars and no verb coming from the amp at all
Distorted: don't mic it like you'll mic a metal amp. Use a ribbon if you can, or place a SM57 slightly off center at a pretty far distance from the amp
Effects: Make sure you have a lot of pedals. Delay is the main tool for every post rock guitar sound
Other:
Synths!! You'll want them, even if you don't tend to use them live. They are amazing for filling the empty space in your mix and lift the whole song to another level. Try Absynth 4, it rocks for this genre
Bad intonation on guitar: Seriously, listen to EITS. Those guitars sound detuned as hell because the intonation is fucked up big time but sometimes that's just what you want
Automation: Use it instead of compressing the hell out of individual tracks.
2-Buss:
I like to do it this way: a touch of convolution verb-> Tube saturation -> EQ -> a little bit of comp or even no comp -> Tape saturation -> limiter (don't squash it to dead)