Certainly with B&W on an Epson scanner it is important to set things manually, otherwise it will blow out the highlights and fill the blacks.  Also, dust removal/Digital ICE doesn't work with B&W as it misreads some of the silver as dust.

I think auto also screws with the highlights in colour. It does take practice to get things to work manually, but once the scan has cut the highlight data there is nothing PS will do to recover it.

You don't say which scanner you have - my experience is with a Nikon Coolscan although I have used my Epson 3200 for scanning some larger format film that won't go into the 35mm Coolscan.

If you have something with ICE and are using color film, definitely use it as there's no real equivalent after the fact. Other than that, the only thing I'd spend time on is making sure you capture all the detail - avoiding the blown highlights and plugged shadows as Paul mentioned.

In general, scanning film is a very time consuming process if you want a decent end result. You'll need to use Photoshop, IMO, and that's a ton better at almost any adjustments you want to make than any of the scanner manufacturer's products or VueScan. So capture at the highest resolution and bit depth your device can handle, ensure you haven't lost data in the scan and leave all the rest to post processing.

If you're doing this for stock, you may have to downsize considerably to get the agencies to accept the end result.