Here's a brilliant slug & snail trap invented by my friend Sophie;
Put out fresh potato peelings, flesh side up, just as the sun is going down.
After dark (but don't leave them overnight), go out with the torch and collect the peelings, which will now be covered in slugs.
The peelings are a lot easier to pick up and dispose of (I keep them in a covered container then feed them to the chooks in the morning) than removing individual slugs from plants.
If you do this steadily for a week, you'll decimate most of the slug population.
If you see any huge spotty slugs - leopard slugs I think they're called - leave them alone as they feast on the slugs that feast on your seedlings.