Also try cleaning your rims with something like a pad scourer and some alcohol - your new blocks should 'bed in' in no time at all, although in the future it can be a good thing to occasionally take them off and give them a quick rub with some sandpaper to the 'glaze' that tends to appear and to also check them for rim-eating metal shards/road bits etc. - also check to make sure that the wear is even on them and they are still mounted square to the rim track.