save your crushed eggshells and surround your most vunerable plants, the little sods hate going over them. Gravel and sand can work, but it has to be a bit on the sharp side.
If you have a pond try to encourage toads or if you are lucky hedgehogs are good.
You can actually eat the snails, mixed with garlic butter and 3 bottles of wine to give you enough dutch courage to put them in your mouth.
Also there is nothing nicer than hearing a bird bashing them to bits on a stone. So make the garden bird friendly.
Don't throw them next door, they have a homing instinct.
I always plant in 5s and 3s but always put in a lettucefor the pests without any protection, then pull it out later when the plants are a bit tougher to eat.