If the lacquer is peeling then your have Top Coat Failure. Respray is the only solution.
If the finish is just not shiny, then the lacquer is still there.. but just not shiny.
You need to polish the beast.
First of all, wash the car.
Then use (if you can) a dual-action machine polisher and a mildly abrasive ("medium") polish. This will remove surface marks and swirls. You'll be unlikely to get a good result polishing badly faded paint by hand.
When you're done, switch to a finer polish and polish it again. A finer polish turns that "medium" polished surface (which will be still quite dull) into a shiny surface.
Now rinse the car.. get those abrasives off.
If your car is black you can next try a glaze. A glaze contains fillers which tend to mask some minor swirls (you're bound to still have some) so can improve the appearance. A glaze does not make dull paint shiny, nor does it protect the finish.
To protect the finish you need a wax or sealant. On a dark car, I'd got for a wax.. (anything with Carnauba wax in it). This is usually applied by hand.. and as your paint will be smoooooooth now, it's actually quite theraputic. Let it dry and wipe it off. Repeat.. 2 or 3 times if you have time/energy left.
If you don't like wax (why not? It smells great!
) you can try a sealant. These last longer than wax.. give a slightly less "wet" look but nice all the same. Suits lighter car better though..
You can tell your paint is beyond help if the lacquer is peeling, or if you can see primer. Mostly anything else can be saved.
Note that polishing erodes the top coat (you are removing some top coat to get the surface microscopically flat and uniform) so if you polish too often or for too long you can induce a top coat failure (i.e. you wear through the lacquer until it's so thin it starts to peel) but this is RARE. It doesn't sound like your car has been polished enough for "thin top coat" to be an issue to you.
It's worth buyinga Dual-action polisher and some kit. It's very difficult to wreck the paint using a DA polisher. For polish, start with the mildest one you have and then only go to the more abrasive one if the mild one isn't abrasive enough.
Everyone and his dog will have their prefered brand or products.. but to avoid confusion (wait till you see all the products recommended) I'd stick to just one manufacturer so that the products you need and how they relate to each other are easier to understand.
I tend to use Poorboys products.. In the scenario above, the products you'd need are;
Medium polish: "SSR2"
Fine polish: "SSR1"
Glaze: "Black Hole" glaze
Wax: "Natty Blue" wax
Once you have your car sorted, you only need to maintain it. Regular washing.. (see "2-bucket method" to reduce new swirling) and claying (see "claying") will prepare the surface... then you just need to glaze and wax it.