Those pesky garden Pests will be out and about in force now so don't be too lax in dealing with them early. It also pays remember that a lot of good garden visitors will be eating them for lunch or dinner! You want to encourage birds, ladybirds, lacewings and more into your garden as they can keep pest numbers down in a big way and are obviously much better for the environment.
In my garden I have a resident thrush that consumes vast amounts of snails – she whacks them on one particular paving slab and leaves the empty shells (and a certain amount of nasty mess!) for me just to prove just how many she has eaten! However the natural predators may not be quite up to the job if there is a really bad infestation, I don't want to destroy ladybirds and other good visitors so I only use Biological Control which I have found to be really effective – especially against slugs! Nemaslug and other Nemasys products do not harm any other wildlife, children or pets and it is really effective.
The other ace I have up my sleeve is Insect Netting - I had such a devastating attack of Cabbage White Caterpillars a few years ago - I woke up one morning and my plants were alive with the horrible green things and my brassica leaves were all lacy! It's not just the holes in the leaves that I hate but the horrible 'frass' (that's caterpillar poo to you and me!) and I just couldn't bring myself to eat any even after washing! So now as soon as they're planted they get covered with Netting so the butterflies can't get near to lay their eggs. Prevention is always better than cure!