Attracting wildlife to your garden can have huge benefits and save you money!

Slugs: Frogs and hedgehogs eat them and their eggs (laid under your soil) - a small pond close by to your habitat can sustain them and help in the constant battle against the slugs that eat your veg and plants.
Butterflies: Allowing things to overgrow a bit, seems to attract more wildlife into the garden.
Midgies: From the little pond, midgies swim around then leave the pond and fly around the garden.
Why would I want to provide a haven for these insects? There's method in the madness, we have a family of bats that live over the back, as the midgies rise as soon as dusk falls, the bats swoop down and eat them! (Don't even bother trying to photograph them, I have been trying to catch them on camera for years, not a single success story to show for it yet hehe)

The link I have included in this post (at the top) has laid out instructions for building your own.
Find a quiet corner of your garden, put down a few paving stones or flags, to provide a solid base for your habitat, turn the bottom pallet upside down and place the next pallet the right way round on top of it, this leaves a big enough space for hedgehogs to get in.

I use my habitat to get rid of grass cuttings and branches I chop off from the neighbours over hanging bushes, this provides great nesting material for the local birds, of which we have many here in Lancashire.
Kestrels, hawks, starlings, etc are common here. We have also seen blackbirds returning to feed, after years of not having them around because of building work dug up most of the natural landscape to the rear of our garden. If you provide materials and foods for them they will come back to any area.
We have even had a rare pair of yellow wagtails feeding.

Once your habitat is in place, don't expect instant results!
It takes a bit of time for animals to find it. In our very small pond that I built alongside the habitat (It is a simple large tub half buried in the ground with pebbles placed in the bottom and around the edge of it) we had to bring in frogspawn, the tadpoles seemed to thrive on it, still swimming around as late as November!
If frogs return to it, only time will tell, come next spring we shall find out!

So far we have had just one grey squirrel burying food around it, but it seems to like it as it provides cover for it from predators like the local cats.
Have fun with your habitat and just leave it be, let it develop its own wildlife as it surely will. Local wildlife we all saw as kids is taken for granted, but the block paving and tarmac revolution has not wiped wildlife out, but forced it to move on to other areas, building a simple habitat, we have found, gives the local wildlife a place to come back to and provides a means of existing alongside building mad Britain.

Instructions for building a wildlife habitat