Roman,
My scanning workflow consists of scanning on an old Epson 2450 flatbed using vuescan and trying to adjust the setting in such a way as to produce a neutral result (highlight and shadow detail, scan as a color negative). I open the image in photoshop CS, convert to BW using channel mixer (red channel). I then tweak the curves/levels to ensure shadow detail and no blown highlights. Convert to greyscale, this is where I sharpen using unsharp mask, no real secrets, just slide the sliders until you get good sharpness w/o halos. I then tone them, switching to duotone (mostly a quadtone) then back to RGB, set mode to "convert to profile" and chose SRGB, save for web and thats it.
I have used "Noise Ninja" for some of my 35mm stuff to remove some scanner grain (I use a minolta dual scan IV and it seems to focus on the grain which accentuates it in the image), Noise Ninja takes care of it if it is excessive, and thats it!
There really is more to do with exposure and processing than scanning, if you don't have a good negative then things are tougher from the start. Xtol 1:1 or 1:3 has made a difference in my pics, a little sharper that D76 and less grain.
Those pics were shot with a Rolleiflex 3.5F with 75mm planar, the lens and the larger format also lend themselves to a larger tonal scale than I get with 35mm, so it isn't just one thing it's everything combined, IMHO 😉 . Here are a couple more:
all on Tri-x 400, Xtol 1:1, Rollei 3.5F