how do you leash train a cat?

Start out with harness training inside. Put the harness on the cat for about five minutes to start with, and play or give a treat to distract him/her from the harness. Gradually up the time spent in the harness over about two weeks, and then add the leash, again only for a few minutes at first, and coax your cat to move around on the leash. A cat won't heel like a dog; basically, you'll be following the cat, and not vice-versa. An H-shaped harness is, IME, better than a figure 8 one, as the latter are too easy to slip out of.
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thanks for the help!

We leash-trained our first cat, to the point that when we picked it up, the little bell on it would bring him running.

Moses is semi-leash trained. He's to the point that he'll tolerate the harness and leash if he really wants to explore outside. We started by putting on a harness regularly, then putting the leash on and letting him lead and sniff things outside.

He's not to the point where I can walk him like a dog, but if we'd tried harder at it, I'm sure we could have got there. I know other people have had success in this.