Foil is thicker, less fiddly and easier to handle than metal leaf, though it will obscure fine details. The adhesive to use is contact cement; water-soluble ("green glue") is safer and easier to use, but solvent-based cement (such as Barge) will dry faster and is usually sturdier. For large areas, a good spray adhesive (such as 3M Spray77) will work, though it often isn't durable enough to withstand prolonged handling.
Applying foil isn't difficult, but there are some useful tricks to learn. First, don't cut the foil into small pieces and then try to apply the contact cement: all you'll do is glue them all to the table. Take a big sheet of foil (a bit more than you think you'll need, as there is some waste) and brush a thin coat of contact cement over the whole surface. I like to spread the cement on with a flat piece of card or thin plastic, to ensure it goes on as thinly as possible. This is especially useful if the glue is old and a bit thick. What you don't want are gobs, blobs or thicker areas that will remain soft after they've dried. While you're waiting for it to dry, brush the other coat of adhesive onto the object to be foiled. Again, try to coat it as evenly as possible, avoiding puddles in crevices and hollows. It's especially important with water-soluble cement to smooth out the air bubbles that inevitably form.
The key to success with contact cement is to let it dry before you try to glue the two surfaces together. Test it by pressing your knuckle to it: if it grips your skin slightly before letting go with a tiny "snick!", it's dry. The water-based cements have the added advantage of changing colour when they're dry: any sign of milky green or white colour means it's not fully dry. A fan and a heater will help on a cool, damp day when things are taking too long.
Lay the foil sheet glue-side up on a flat board and cut it into useable pieces with a sharp blade. As with scrimming, the more complex the shape to be covered, the smaller the pieces will have to be. A bit of experience will tell you what size and shape work best for different types of surfaces. Don't try to tear the foil, because the glue layer will not allow it.
Press the pieces of foil down onto the glued surface, allowing as little overlap as possible. Remember that the foil will not adhere to its own unglued side. Any unavoidable overlaps can be trimmed away with a sharp blade. Because foil doesn't stretch, it will wrinkle slightly over any surfaces that are not absolutely flat. Don't worry too much about this, as all but the largest wrinkles can be burnished down until they don't show. Just aim for as smooth a surface as possible.
At this point it'll just look like you've covered something with tinfoil. Now you have to burnish it to smooth out the surface and make it look like metal. The absolute best burnishing tool I've found is a smooth piece of bone or antler. A smooth piece of hardwood will do as well, though it may take more work to use. Rub the every bit of the surface with the burnisher, including all the ridges, nooks and crannies. As you work, it will smooth out and become surprisingly real-looking. Don't worry too much about small tears and gaps in crevices - these will usually disappear in the breakdown process.