Here's what I do...
Scanning Prints.
1. Clean Glass
2. Make sure the scan settings are suitable. I scan prints for web use at 300dpi unless it's a real little print and I want to get more pixels to make it bigger. Scanning softwares sharpening off (it's do agressive)
3. Do a preview scan
4. Select the area I want to scan
5. Hit autolevels option.
6. Assess if I need to manualy tinker. I might want to change the scan profile to 'open shadows'. I do usually do this as I prefer to get all the shadow detail and alter the final look in the image editing porgram (Photoshop in my case)
7. Scan
8. Hit Autolevels option in PS. Decide if that's better, otherwise undo it.
9. Bring up the levels adjustment box and move the mid point to ensure shadows and midtonesare where I want them. Might alter the black and white end points too, especially if I didn't like the Autolevels attempt at it.
10. Fix any scanned dust spots (sometimes do this)
11. Run "unsharp Mask". I'm lazy and use one setting but if you're trying for quality you should do it based on the image. I use minimal sharpening as it can introduce jaggies and artifical high contrast lines that look terrible.
12. Resize to 548 pixels high.
13. Run Unsharp Mask again.
14 Save for Web as .jpg using whatever compression is necessary to get the file size down to 100-150kb.
Film.
Pretty much the same except in step 2, I change the resolution to the scanenrs best native resolution (1600dpi). I also run step 11 twice. I scan B&W negs as greyscale cause it's much faster then the colour option that many use (I used to too). I used to have all this in an 'action' (a macro) but haven't updated it to suit the resizing height that I now use... must get around to fixing that as the action then runs in seconds from minimal buttons presses rather than doing all the steps manually (although they don't take that long.. maybe 1-2mins plus actual scan time). Did I say I'm lazy...