I usually start with the drums, but only because it is a single instrument with multiple mics, so to be able to treat it like a single instrument it needs to be roughly mixed. It will get worked on again later when the mix comes together.
Bass next, then the guitars, keys etc. Then I treat the band as a single instrument while I sort out the vocals for tone and levels, etc.
Then I listen to the mix as a whole and adjust it all again, and again, making sure everything can be heard, especially the vocals, then look for any problems with mix clarity.
Finally does the mix now sound any good? If not roll around it all again. I constantly adjust things while the mix is playing on loop, sometimes things I do are undone again if they don't work.
And don't forget to change the volume, listen soft, listen loud, does it still sound good at all volumes? Multiple monitors if you have them.
And take breaks, leave the mix for half hour and leave the room, coffee, food, freash air, then come back, what does the first play after a break sound like?
Hope this helps, it's hard to explain mixing, to me its almost meditation I get so connected to it.
Alan.