I have found it helpful to refrain from mulching beds when slugs are really bad, to water in the morning so the surface of the soil is a bit drier by evening when they come out to feed, and to use a combined approach of beer traps and diatomaceous earth. I can't emphasize enough that mulch provides very attractive conditions for slugs, and the trade off for eliminating mulch is not nearly so high for fall crops.

The advice given in Slug Stoppers (from Organic Gardening magazine) pretty well covers the options.