I use sterling silver and copper to make my jewellery designs and looking after them correctly means that you'll get many years of enjoyment from wearing them. I've put together a few tips and considerations for you.
Store your jewellery in a box when not wearing, or better yet a zip lock bag with an anti tarnish tab inside. Oxidisation is the biggest culprit of tarnishing silver, taking it from that lovely shiny silver to a dull blackened colour. This does not mean it is not real silver, in fact more of an indication that it is sterling silver. Keeping your jewellery away from the air when not wearing is a good way to slow down this natural process.
Polish your jewellery to remove natural skin oils, body and beauty products and contaminants transfered from the air. If you give your silver jewellery a wipe over with a silver polishing cloth before putting it away it'll keep it tarnish free for longer. Copper will also oxidise and tarnish, think of the different colours you can find in pennies and two pence pieces. You can buy copper polish to keep your copper shiny, you can also use lemon juice and salt making sure you wash off and dry thoroughly afterwards, or you can embrace the natural change in the metal.
If applying perfume or creams to your skin then do so before putting on your jewellery. These can dull your jewellery and also quicken the tarnishing process so to keep your jewellery cleaner let your favourite products soak in and settle before putting on your jewellery.
Remove jewellery before bathing or swimming. Whilst water itself isn't harmful to silver the products you wash in and the chlorine in a swimming pool and hot tub can be very damaging and quickly turn your silver black. The best thing is to not wear jewellery whilst you bathe, swim or soak. Copper also is not a great fan of water creating a reaction resulting in verdigris, when the metal creates a green coloured coating which will rub off onto your skin, this is not toxic and can be washed from your skin with soap and water.
Notes on my copper pieces. I do coat each of my copper pieces with a clear metal lacquer or wax to help with resistance to moisture and oxidisation but this will naturally wear away. You may notice extra polishing is required when this happens and you can either embrace the natural changes or polish it up and recoat it yourself with metal lacquer, renaissance wax, or on a budget clear nail varnish can work well, but always try it on a discreet area of the copper first.