Setting up your bin
Ideally site your compost bin in a reasonably sunny spot on bare soil.
The reason you should site your bin on soil is that it makes it very easy for beneficial microbes and insects to gain access to the rotting material. It also allows for better aeration and drainage, both important to successful composting.
On wire mesh
If you're worried about vermin becoming a problem, adding a wire mesh base to your bin when you set it up can help avoid problems later. To do this you need to dig a shallow hole (approximately 1 inch deep) that is equal to the diameter of your bin. Cut a piece of wire mesh to slightly larger diameter than the base of your bin and place it over the hole. Place your bin on top of both.
If it is possible to remove the paving below the compost bin, then this is the best solution for paved or courtyard gardens but, if not, there are a few things you need to bear in mind.
Some liquid might seep out of the bottom of the bin and stain paving both underneath the bin and sometimes around it. If this is likely to be a problem, then you should consider building a small raised bed filled with soil to put your compost bin on.
Liquid should be contained within the soil in the raised bed and you can always plant up around the bin to make it a feature. If you are putting your bin onto old paving and staining is not an issue, you will need to introduce the soil-dwelling organisms manually.
You can do this by adding a shovelful or two of soil to the bottom of the bin or, better still, get some home compost from a nice mature bin. It may take a little longer for your bin to get started but it will soon be full of life.
It is best not to put a compost bin directly onto a deck as the liquid that sometimes seep out of the bin will stain it. The only real solution here is to build a raised bed directly on top of the deck.
You can use deckboards to build your raised bed so that it compliments the deck. Seal the deckboards under the bed with decking seal, just to be on the safe side, then line the bottom of the raised bed with plastic to protect the deckboards underneath and cut some drainage holes though the plastic where there are spaces in between the deckboards.
Fill the bed full of soil or peat-free compost and this will capture any liquid that seeps out. Anything you plant in the bed around the bin will be nice and healthy because it will be getting a good liquid feed.
You can easily put your bin onto gravel, whether it be in a gravel garden or on a gravel driveway or path. If you have laid a membrane beneath the gravel, you will need to cut a hole or slits in the membrane so that the soil-dwelling organisms can get through.
If you are concerned about compost messing up your gravel when you empty the bin, you will need to lay out a plastic sheet to keep the gravel clean when it is time to empty the bin.
If you must place your bin on concrete, remember to add a thin layer of soil to get it started. This will help attract worms and other beneficial organisms.
Screening your compost bin
If space is limited and you don't have an out of the way corner in which to put your bin, you can screen it from view by using live plants, a trellis, bamboo or willow.