Wow, all sorts of stories.
Everyone has their own perspective and history.
To be sure, if your Bimmer has just RWD your most important physical need is true winter tires. There are many good ones, we've had very good experience with Bridgestone Blizzaks. After that it's mostly about you.
We certainly don't get winters here like the folks up north but our 6-10 ice storms each year along with a few 4"-8" snows have a way of teaching one to drive 'patiently' and deliberately. Plan ahead. Think ahead.
Yes, throw a little weight in the boot but it's mainly about using your head and like mentioned earlier, get a little practice (in a safe place) learning your car's manners before you need to know them.
It often works well to drive in higher gears than normal. On ice I usually start out in 2nd and move into third within a few feet. This low RPM along with Gentle throttle management help avoid wheel-spin and fishtailing. The rest is just common sense.
In recent years we've been spoiled as we've had BMWs with xDrive and we've never been 'stuck' in one. We've run nothing but all-seasons on these vehicles. I've pushed through snow halfway up to the headlights, negotiated more miles on ice than any sane person should and driven in -20 degrees F ... on all-seasons. However, Blizzaks on the xDrives would be even better.
Someone above said that his 4-series didn't do as well in snow as a prior 3-series. Our experience with E39s, E46s, E90s, X3s and now a 428xi has been pretty consistent. There are certainly things about the newer generations that we don't like as well as the earlier cars but they still get us around quite nicely.
Enjoy the ride.
E30 325is . . . . . . . . . . . . . . . Fun little Rascal
E39 540i Sport . . . . . . . .ah-hhhh ... Hated to let her go but, after 10+ years it was time
E90 330xi Sport. . . . . . . Oh, we should have kept that one
E90 335xi Sport. . . . . . . Hallelujah ... GONE !
F25 X3 28i . . . . . . . . . . .Wife's first SUV -- traded
F25 X3 28i 2.0T . . . . . . . Her 2nd SUV -- traded
F25 X3 28i 2.0T . . . . . . . . . . Wife's newest ride
F36 428xi G.C. M-Sport . . . . Highway Cruiser