Are you talking about sterling and silverplate? You can start by getting a jar of standard silver cleaner at the supermarket or the hardware store. I'd avoid the really strong stuff (like TarnX) at first if I were you - just buy the regular cleaner. Follow the directions on the container. When silver gets dirty, it isn't dirt - it's tarnish; and tarnish eats away at the silver.
It's amazing how a little cleaning will usually bring out the best in silver - but if it doesn't work well enough, ask a reputable jeweler about the best thing to do next. With a valuable item, it is possible to re-silver, but it's expensive.
Silver tarnishes faster, I think, in winter months, because of the furnace running. Once you have your things clean, it doesn't take much time or effort to do a regular cleaning and polishing to keep them that way (it certainly doesn't take as long as a major overhaul!).
I soak my stove pans and then clean them with hot water and SOS pads. When they get really bad-looking no matter what I do, I replace them. You can get replacements for most stove pans at hardware stores. Be sure you get the right ones for your stove.
Hope this helps.