Don't be a gaper and get all dressed in the parking lot. Roll your gaiters over your baggy snow pants and proceed to the lodge like a normal human being. I try to minimize the amount of time my ski boots spend NOT in my skis. Wearing them across pavement/concrete does slowly wear out the heel/toe lugs. If you have replaceable ones, that's fine. But if you don't, those will eventually shrink the contact points to your bindings, which, is pretty darn essential to binding safety/proper function.
Temperature. is. key. I always keep my boots "warm" and dry. As stated, remove the liners, especially after a shuper shloppy shpring day. Don't drop them on top of say... a baseboard heater or hot air duct. Since so many boots these days have heat adjustable liners it is essential to maintaining fit that they dry either slowly/naturally or through a boot drier. Radical shifts in temperature will make you go "wtf bro, I'm not a foot bound Chinese woman, what happened to my boots."
The same goes for the plastic, it will expand (and contract when it cools) in weird, inconsistent ways. Returning to the original is not easy.
Don't leave your boots in your Thule/Yakima/Sears Box during travel. I usually keep mine in the passenger side floor (I tell my friends to deal with it) and keep the warm air lightly flowing. (Old Subaru=little drafty)
Buckle your boots--DO NOT clamp them down--when not in use. After lots of personal experimenting this is my advice: ratchet them so that when you pull them down the plastic is lightly pulled in to place and has a *touch* of play. This could be different for you, experiment.
Figure out a good transport system. Hopefully a boot bag.