We've been cutting back for a few years.
I haven't reduced the amount I spend on wine for dinner, but I now buy only 2 bottles of a nice wine to match our meal rather than a bunch of cheaper wine that we might or might not enjoy but would probably just drink much quicker. We might not even open the 2nd one, but it's nice to have the option if we do actually get home in time to utterly relax (mass, family visits etc) and savour it (and not get nearly so squiffy!).
We also don't tend to buy much by way of sweet treats - we don't buy any boxes of sweets or tins of biscuits (we do get given some). I will spend €10 on a large bag of Leonidas orangettes, as our sweet treat for the family, and we spread that out over the week or so. And I will get a load of packets of biscuits that we enjoy, so that if we have visitors, I will have a choice to offer, but I won't have loads left that we feel we "must" eat, as most are still sealed and we can open a single packet as we want later at our leisure and normal pace of eating biscuits.
We no longer buy 2l bottles of fizzy drinks. But we will buy cans of fizzy drinks instead - a choice is available then for visitors (and ourselves) but there is no pressure to use them up before they go flat. And the cans can last a long time after Christmas as well if they are not used. (We do the same for tonic, normally only buying cans, but we will actually buy a bottle for Christmas as we drink more and we will have visitors who drink it, so it's not wasted then). And we often only buy the small "mixer" sized cans of coke etc, rather than 330ml cans, for drinking during the year as that is enough for DD (the usual drinker of those).
We also buy the individual portion packs of crackers (for the cheese) - we get a few different types for variety but there's no point in buying a tin which includes up to half of things we don't like and will go soft quickly. And what we don't open, we can open another time when we have some cheese on a more normal night.
I will buy more of some things - that we use a lot of anyway and there are special offers at Christmas. Like the 50% extra free large jars of Hellmans - which last until well into the summer and we will use up, so I will take advantage of those savings. Or jars of curry sauces (for turkey leftovers) that we use for easy dinners some nights when school and work is manic.
For presents, my Siblings and I do a Secret Santa and stockings - reduce/reuse/recycle/homemade or spend €5 or less on each stocking item (1 for everyone), and each person gets 1 large present in the secret santa (max €50). So everyone only buys 1 large one (and perhaps some smaller stocking items - there is also one item that seems to go around every year and land in someone's stocking as the "gag" gift!), and everyone gets both one larger present and a decently filled stocking. That works well.
I want to try to simplify things a little more though, now that DD is getting a bit older.