Once you've mixed enough songs, you start to develop automatic habits that can be real time-savers. For example, You might always arrange the tracks so that the guitars are on tracks 1 and 2, the bass on track 3 and the lead vocal always on track 4, etc. You might then also have automatic habits like immediately reaching for certain effects (EQ, compression and so on) on your tracks and even start dialing up settings for those effects before you've really even listened to the mix.
But it might be prudent to stop all that and just listen first before you do anything. Take stock of what you've got when everything is raw and do more listening before you do any acting. This is good advice that I will be taking for my next mix since I read Graham Cochrane's article this morning - Stop And Think Before You Mix.
Check out his article here: http://therecordingrevolution.com/2012/11/12/stop-and-think-before-you-mix/