I don't know how to mix the kick and subbass
What I'm doing is I'm using the sidechain compression method
How about the EQ? from what hz range should the kick be where it doesn't clash with the subbass, or how should the subbass be eq'd
As Mat mentioned,really quick sidechaining , but that isn't always getting good enough results .The best way I find is actually cutting a hole in the element I want ducking and tailoring the volume curve to the curve of the kick/whatever I want prominent for that split second .I also look at a bus with both sources going to that and make sure I manage to keep the volume about the same as when the kick/snare goes by itself to maximise headroom overall .A loud,punchy mix is made on the channels,not the master .-TeeBee
Do you have any tips on getting rid of sidechaining clicks? this is something thats always bugged me
Yo Mat, one really easy way to get rid of the clicks on the sub is to put a low pass after the sidechain and filter out the click 
only works for sub though since you probably wouldn't want to filter out harmonics of other sounds
Yeh, I do this sometimes, but it still adds a 'lump' where the transient should cut it out completely. I guess I'll just have to do it the long way like TeeBee said...
BUT IM SO LAZY!!!!!!!!! WAAAAAHHH 
Maybe a little late but the Live 8 compressor does not have any click in it because of the algorithm. I believe you can still find it online
