heperding cats only works insofar as the cats in question are willing to cooperate.
When we first moved in to our present home, we were eager to put up the cat fence which had proved so effective at our last place of residence. This consisted of metal stanchions affixed to and extending above the existing fence, angled inward and strung with nylon netting. However, although we got permission from the landlord, one of our neighbors was very insistent not only that we not attach anything to the fence, but also that they did not want to see even one inch of netting visible above the fence.
This was discouraging enough to halt any definite plans. For the next 9 months we settled for only letting the cats out while supervised. This worked tolerably well, but as I said, it really depends in some degree on the cats' cooperation. I suppose these short winter days have been getting to Gabriel, because lately he fairly regularly has been making a mad dash to the perimeter and jumping the fence, forcing us to go hunt him down and retrieve him from wherever he decided go exploring. (He got out of the yard on Christmas morning, and came home smelling like hickory smoke. I suppose he decided to check out what sort of yummy Christmas dinner the neighbors were cooking in their smoke box!)
Well, enough is enough. This past week I did a little shopping around to investigate my options, and bought some fencing materials. One of the most important things we learned from the last cat fence is that if the cat doesn't think the fence is sturdy enough to support its weight, it won't try to climb over.  So, the fencing material needs to be lightweight and flexible, and it just needs to be tall enough that the cat can't hop over it.
I found what I needed at Lowes. I got some 5' posts, some 4' black netting, cable ties, and metal fence wires to stake the netting to the ground between posts. Thursday I started cleaning up the yard, trimming the hedge, the grass and the weeds where the fence was going to go. Today we finished the yard work and set up the fence. Looks great! We let the cats out to investigate, and no one tried to escape. A few more supervised excursions to make sure all is secure, and I think we can start letting the kitties out to play as long as they want. That should make everyone happier!