I've tried slug traps, beer, crushed egg shells, sand from the beach (for the salt content), as well as a few other home remedies. None of them worked well.
Don't wait for the slugs to appear if they are in your area. Buy some good quality pellets and sprinkle a ring around your plants as soon as you put them in the ground (about a foot away from the stalks should do). A slug can munch clean through a seedling in one feeding so waiting for them to appear is the first mistake people tend to make.
Repeat every couple of weeks or after periods of heavy rain - more often if you have lots of very small plants and lots of slugs (keep an eye on the pellets and replace when you don't see them any more).
Be careful with things like beer. The smell can attract the slugs from a distance and lead them right to your plants - I know this is the idea but if they have to cross 10 feet of plants to get to the beer, they may stop for a snack along the way.
I've been mostly slug free for two years now and I live near the ocean where they are rampant.
I also like to take a piss several feet away from my outdoor plants when I visit them. Many wild animals shy away from the sent of human urine - we are surrounded by deer but they leave my plants alone.