One of the easiest ways you can help yourself get a good scan is to start with a clean original. Buy yourself an anti-static brush for cleaning reflective art (prints, documents). It’s also very handy for cleaning your scanner’s glass – scanning old photos and documents is a musty, dusty endeavor. Use it all the time. Get in the good habit of brushing your scanner and your original before every scan.
This may sound like OCD, but it’s just a good idea. Scanners magnify every dust spec and bit of fuzz; it makes sense to get as much of that off an original as possible before you immortalize it, or you’ll end up spending untold hours touching up your scans in Photoshop. Or worse, sharing a bunch of cruddy photos with your family. Don’t kid yourself – they’ll notice.
I use a Kinetronics StaticWisk, which is available in several sizes from Amazon.com and Buy.com. Don’t cheap out on this one. A good brush makes all the difference.
To clean slides and negatives, you can also benefit from having a can of compressed air close at hand. These are available at most any office supply or art supply store. Here’s one at Office Depot. Just be sure to test the air can on a table top or your hand before you aim it at your slides. Sometimes the first spray can come out wet.