This technique is quick and gives the look of metal. It is best done over relief but still looks good on a flat surface.
Using  ordinary household tinfoil you can really change the look of an object or you can also incorporate it into a piece of art.

Decide what you want to use as relief for your piece. I used precut letters DREAM and some other bits I found around the place. You can cut your own letters or shapes out of cardboard or use things like metal washers, buttons or anything you find around the home. Glue them using PVA or other glue onto your background

Take a piece of tinfoil about twice the size of your backing board and scrunch it up into a ball then very carefully open it out so that it is big enough to cover your board completely. If you are doing a large piece you can do this in sections to make it easier to handle. At this point smear a heavy layer of glue over you relief pattern and press the foil over it. Press firmly with your fingers to push as much of the foil to the suface as possible.

With a smooth tool, the back or handle of a teaspoon, a bone folder or similar gently go around the edges of your letters etc so that the foil is pressed firmly to the background. This will highlight the pattern

When you are happy that the foil is stuck and the relief looks OK the paint it all over. Before it is quite dry rub a little of the paint off to expose the foil underneath. You can have a lot showing or just a little, you can decide. 

Then paint all over it again with black or burnt umber. Once agin when nearly dry just rub back enough to get the look you want. You can leave it as is or seal it with a gloss which will make it 'pop'!.
Different colour combinations will give different outcomes so have a play. You can get really cool finishes with blues and reds or oranges and greens. Just gold or bronze acrylic paint over the foil also looks great.
have a go and see what you come up with.