I was staining some cabinets and I had an accident,so that prevented me from removing the excess stain with a cloth. That left them with brush marks on them. How do I fix that? I do want my stain to be dark. That's how they turned out, but I do not want it streaky. I haven't done anything else on them,but put that first coat of wood stain on them.

Try making the same mistake an a piece of scrap wood, let it dry all streaked. In a day try wiping down your new accident:first with a rag and paint thinner, next a rag and denatured alcohol and finally laquer thinner. One of those solvents should remove much of the excess, usually paint thinner is all that's needed