I start on full, pushing the lever as far as it can go, after the engine starts, I usually am putting on my jacket gloves backpack, then reduce the lever to the half detent, depends on the day .
Opening the throttle before the engine is firing can cause hard starting .
Ride with the lever in the half detent about half mile or so (after my first stop light), then close the lever .
I leave for work at a little after 0500, so I don't have much traffic to deal with, so I go easy on the throttle until I get on the expressway after about two miles .
You'll have to find out what procedure works best for you through trial and error .
Cold start oil pressure can exceed 150 psi, that's probably why there are collapsed oil filters, as Monte has said a bit of warmup and a light hand on the throttle in the first couple of minutes .
Keeping your battery on a battery 'tender' is a good idea as well, especially during the cold weather .
I never thought much about battery tenders, but after using them for about two years, whenever my bikes are parked for the day in the garage, they are on a battery tender, I'm sold on them .
I've got them on four bikes and one four wheeler .