What color cloth and what stained it? There are some stains like newspaper ink on light colored upholstery than nothing will remove. New blue Jean's is another stain that's difficult to remove on light upholstery.
After you remove the stain, clean the seats and treat the upholstery unless the seating is not supposed to be treated.
Any of the upholstery treatments like Scotchgard work fine. I only treat the seat and not the back mainly because of the cost of the stuff, plus the backrest really doesn't need protection like the seat. Best to test a small location to be safe.
As far as cleaners, I also use Tuff Stuff. I think Chem Guys also puts out a product that has to be mixed with water. And I heard that a concoction of soap and water will also work though I've never tried it.
I wish the OP would post what type of interior and color and what type of stains they have.
My favorite for cleaning upholstery and carpet has always been Ivory dishwashing liquid and warm water. Use only a few drops of it, all those suds are difficult to pick up and don't do a better cleaning job.
You can pre-treat stains with a tiny bit of Ivory and agitate gently with a soft-bristled toolbrush.