Ok I used to work in a shop many years ago so I'll give you the quickest boot buying advice I can without going on and on here. The very first thing you've got to realize going in is NEVER cheap out on boots. They can make or break your day because they are the only piece of equipment that comes in direct contact to your body. A bad boot can ruin your day fast.
That said get your foot sized and boots fitted by a qualified shop. It helps a lot and once done you're pretty set to buy boots and be confident about your size. But boots should fit tight at first and you should try to size at least a half size down from your normal sneaker size. Example I wear a size 10.5 sneaker normally (DC, Etines, or DVS) my boot size is a 10 even. Reason why, over time your liner will pack out a half size from use alone.
Next for comfort sake unless your riding gnarly backcountry lines I would say try to stick with a stiffness rating between 6 to 4 this gives you good support all over the mountain without feeling like the boot is restricting movement. Also try to pick a boot with an articulating cuff, it allows your ankle to flex easily inside the boot making it more comfortable.
If there is the slightest amount of pain take off the boot and try a different model. Something that hurts in five minutes and annoys you. Will feel like pure torture in an hour or so.
Try MANY different brands, some will feel great others won't let your feet decide on the brand and not your eyes or your friends. Wear each one for a bit in the shop like five to ten minutes. Your feet will swell a bit while in your boots this is very normal. When trying them on your toes should touch the very end of the boots toe box without being cramped. As you use them that feeling of being close to the boots toe box will fade as they break in. Finally don't let the price tag scare you off, if they work for you get em. Nothing is worse than taking the cheaper brand that fit ok and finding out they suck two hours in.
If you go to a shop and have your boots fitted make sure they are a good fit to your current bindings. Especially if you buy BURTON, reason for this is the foot shrinkage technology they use in some of their high end boots. This can cause your bindings to fit poorly if your foot size drops below the recommended size range. Also some boots also do not fit well to some bindings as well. So make sure you check it, if you can bring your board, if not bring one binding, or ask the shop. They may know the answer, and if they don't try your new boots on with your board before hitting the hill at your house. The fit might be good but you might have to adjust the strap length.
Finally when you've chosen your boot if you like get them heat molded, I'm not a fan of heat molding due that I feel it degrades the liner and caused them to break down quicker, hence early pack out. I like breaking my boots natural by riding them for a few days on the hill. But do consider a nice pair of custom orthotic foot beds. Spend for them to be molded in the shop, it's an item you can buy once and use in many pairs of boots. Worth the extra money spent easily. Finally if you have boot dryers great, if not get a pair even the cheapest will do here. Nothing ruins boots like funk, and once they are funky it's very tough to get rid of it. By drying your boots you'll find they last even longer.
Good luck and hope you find a great pair of boots. I use a lot of 32 boots over the years. My favorites are the Lashed with the traditional lacing. I found the fast track models to be a little stiffer than the laced version.