Plant some hedges in your garden. Or even better, replace your fencing with hedges.
2. Create a hole in the ground/fence
Hedgehogs need a place where they can get into your garden, you need to make your garden accessible to hedgehogs, so they can get the benefit out of it.
3. Leave the pesticides/slug repellent
These are not only harmful to hedgehogs, they are harmful to other wildlife, and pets. Hedgehogs naturally eat slugs anyway, and its an organic, and environmentally friendly way.
4. Leave the grass!
Don't create an artificial garden with plastic grass, or paving over the grass.
5. Buy a hedgehog house
You can buy hedgehog houses online, on places such as Amazon. This is particularly handy if you are waiting for hedges to grow - as they do take a lot of time to grow.
6. Water and food
Have a water dish for hedgehogs. Don't put milk out for them, or bread! You can buy specialized hedgehog food, again, Amazon is a good place to go for that!
But, hedgehogs can also eat cat and dog food, they also like chocolate.