Well as you may see in the long greyhound posts. I did a lot of trifectas.

Mainly I eliminate the ones that wont place. I choose the best two chances. Have them for first. THen choose three more than I reckon can run a place. eg: 1,2/1,2,3,4,5/1,2,3,4,5 and that will cost $24. It seems to work.... but i kept on missing 1 leg or the wrong winner popped up. But it did work twice.